unit 1 – java network programming j… · prashant maheta, ce department | 2160707 1. discuss the...

Prashant Maheta, CE Department | 2160707

1. Discuss the URL and URLConnection class with their use in network programming.

The URLConnection class is used to connect to a website or resource on a network and get all the details of resource on a website. The Java URL class represents an URL. URL is an acronym for Uniform Resource Locator. It points to a resource on the World Wide Web. For exam

http://www.darshan.ac.in A URL contains many information:

Protocol: In this case, http is the protocol.

Server name or IP Address:

Port Number: It is an optional attribute. If we write http//ww.80 is the port number. If port number is not mentioned in the URL, it returns

File Name or directory name: In this case, index. Using OpenConnection() method of the URL object, we can contact with the resowebsite is established :

import java.io.*; import java.net.*; import java.util.*;

class Details { public static void main(String args[ ]) throws Exception //pass the site url to URL object URL obj = new //open a connection with the site on Internet URLConnection conn = obj.openConnection();

//display the date System.out.println("Date: "+ new Date(conn.getDate())); //display how many bytes the index.html pag int l = conn.getContentLength(); System.out.println("Length of content: "+ l);

if(l == 0) System.out.println("Content not available"); return; }

Unit 1 – Java Network Programming

2160707– Advanced Java

iscuss the URL and URLConnection class with their use in network programming.

class is used to connect to a website or resource on a network and get all the details of resource on a website.

class represents an URL. URL is an acronym for Uniform Resource Locator. It points to a resource on the World Wide Web. For example:

darshan.ac.in

contains many information:

In this case, http is the protocol.

Server name or IP Address: In this case, www.darshan.ac.in is the server name.

It is an optional attribute. If we write http//ww.darshan.ac.in80 is the port number. If port number is not mentioned in the URL, it returns

File Name or directory name: In this case, index.jsp is the file name.

Using OpenConnection() method of the URL object, we can contact with the reso

public static void main(String args[ ]) throws Exception { //pass the site url to URL object URL obj = new URL("http://www.microsoft.com");

//open a connection with the site on Internet URLConnection conn = obj.openConnection();

//display the date System.out.println("Date: "+ new Date(conn.getDate()));

//display how many bytes the index.html page has int l = conn.getContentLength(); System.out.println("Length of content: "+ l);

{ System.out.println("Content not available"); return;

Network Programming

1

iscuss the URL and URLConnection class with their use in

class is used to connect to a website or resource on a network and get all

class represents an URL. URL is an acronym for Uniform Resource Locator. It

is the server name.

darshan.ac.in:80/index/ 80 is the port number. If port number is not mentioned in the URL, it returns -1.

Using OpenConnection() method of the URL object, we can contact with the resource on a


else { int ch; InputStream in = conn.getInputStream(); //display the int i = 0;

while((ch = in.read())!=

} } }

2. Explain Socket, ServerSocket, InetAddress classes. Write a java program to find an IP address of the machine on which the program runs.

Socket :

For implementing client side sockets this class is useful. It accepts two arguments ipaddress and port no.Socket s = new Socket(“localhost”,777)

ServerSocket :

For implementing server side sockets this class is useful. It accepts one no. ServerSocket ss = new ServerSocket(777)

InetAddress :

The java.net package provides an Address, some of the methods are : getLocalHost() method will return the object of InetAddress ClassgetHostAddress() method then will return

Example : GetIPAddress.java

import java.net.*; import java.io.*;

public class GetIPAddress {

public static void main(String [] args) try {

InetAddress thisIp =InetAddress.getLocalHost();



InputStream in = conn.getInputStream();

//display the content of the index.html page int i = 0; while((ch = in.read())!= -1)

System.out.print((char)ch);

Explain Socket, ServerSocket, InetAddress classes. Write a java program to find an IP address of the machine on which the

For implementing client side sockets this class is useful. It accepts two arguments ipaddress and port no. Socket s = new Socket(“localhost”,777)

For implementing server side sockets this class is useful. It accepts one

ServerSocket ss = new ServerSocket(777)

The java.net package provides an InetAddress class that allows you to retrieve the IP ddress, some of the methods are :

method will return the object of InetAddress Class method then will return the IP Address of the Local System.

Example : GetIPAddress.java :

public static void main(String [] args) {

InetAddress thisIp =InetAddress.getLocalHost();

Network Programming

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Explain Socket, ServerSocket, InetAddress classes. Write a java program to find an IP address of the machine on which the

For implementing client side sockets this class is useful. It accepts two arguments

For implementing server side sockets this class is useful. It accepts one argument port

class that allows you to retrieve the IP

the IP Address of the Local System.


System.out.println("IP Address of this System:"+thisIp.getHostAddress()); } catch(Exception e) { e.printStackTrace(); } } }

3. One-way Communication using Connection(TCP)

Example : TCPServerOneWay.Java

import java.io.*; import java.net.*; class TCPServerOneWay { public static void main(String args[ ]) //Create a server socket with some port ServerSocket ss = new ServerSocket(777); //let the server wait till a client accepts connection Socket s = ss.accept(); System.out.println("Connection established"); //attach output stream to the server socket OutputStream obj = s. //attach print stream to send data to the socket PrintStream ps = new PrintStream(obj); //send 2 strings to the client String str = "Hello client"; ps.println(str); ps.println("Bye"); //close connection by closing ps.close(); ss.close(); s.close(); } }



System.out.println("IP Address of this System:"+thisIp.getHostAddress());

catch(Exception e) { e.printStackTrace();

Communication using Connection-Oriented Prot

Example : TCPServerOneWay.Java

public static void main(String args[ ]) throws Exception { //Create a server socket with some port number ServerSocket ss = new ServerSocket(777);

//let the server wait till a client accepts connection Socket s = ss.accept(); System.out.println("Connection established");

//attach output stream to the server socket OutputStream obj = s.getOutputStream();

//attach print stream to send data to the socket PrintStream ps = new PrintStream(obj);

//send 2 strings to the client String str = "Hello client"; ps.println(str); ps.println("Bye");

//close connection by closing the streams and sockets

Network Programming

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System.out.println("IP Address of this System:"+thisIp.getHostAddress());

Oriented Protocol


Example : TCPClientOneWay.Java

import java.io.*; import java.net.*; class TCPClientOneWay { public static void main(String args[ ]) throws Exception //create client socket Socket s = new Socket("localhost", 777); //to read data coming from server, attach InputStream to the socket InputStream obj = s.getInputStream(); //to read data from the socket into the client, use BufferedReader BufferedReader br = new BufferedReader(new InputStreamReader(obj)); //receive strings String str; while((str = br.readLine()) != null)

System.out.println("From server: "+str); //close connection by closing the streams and sockets br.close(); s.close(); } }

4. Two-way Communication using Connection(TCP)

Example : TCPServerTwo

import java.io.*; import java.net.*; class Server2{ public static void main(String args[ ]) //Create server socket ServerSocket ss = new ServerSocket(888);



OneWay.Java

public static void main(String args[ ]) throws Exception { //create client socket with same port number Socket s = new Socket("localhost", 777);

//to read data coming from server, attach InputStream to the socketInputStream obj = s.getInputStream();

//to read data from the socket into the client, use BufferedReaderBufferedReader br = new BufferedReader(new InputStreamReader(obj));

//receive strings

while((str = br.readLine()) != null) System.out.println("From server: "+str);

//close connection by closing the streams and sockets

way Communication using Connection-Oriented Protocol

TwoWay.Java

public static void main(String args[ ]) throws Exception {

ServerSocket ss = new ServerSocket(888);

Network Programming

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//to read data coming from server, attach InputStream to the socket

//to read data from the socket into the client, use BufferedReader BufferedReader br = new BufferedReader(new InputStreamReader(obj));

Oriented Protocol


//Create server socket ServerSocket ss = new ServerSocket(888); //connect it to client socket Socket s = ss.accept(); System.out.println("Connection established"); //to send data to the client PrintStream ps = new PrintStream(s.getOutputStream());

//to read data coming from the client BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream())); //to read data from the key board BufferedReader kb = new BufferedReader(new InputStreamReader(System.in));

//server executes continuously while(true) { String str,str1;

//repeat as long as client does not send null string

while((str = br.readLine()) != null) {

}

//close connection ps.close(); br.close(); kb.close(); ss.close(); s.close(); System.exit(0); //terminate application } //end of while } }



//Create server socket ServerSocket ss = new ServerSocket(888);

//connect it to client socket Socket s = ss.accept(); System.out.println("Connection established");

//to send data to the client PrintStream ps = new PrintStream(s.getOutputStream());

//to read data coming from the client BufferedReader br = new BufferedReader(new

InputStreamReader(s.getInputStream()));

//to read data from the key board BufferedReader kb = new BufferedReader(new

InputStreamReader(System.in)); //server executes continuously

String str,str1;

//repeat as long as client does not send null string

while((str = br.readLine()) != null) {

System.out.println(str);

str1 = kb.readLine();

ps.println(str1); //send to client

//close connection ps.close(); br.close(); kb.close(); ss.close(); s.close(); System.exit(0); //terminate application

} //end of while

Network Programming

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5. One-way Communication using Connection

Example : UDPServerEx.Java

//A server that sends a messages to the clientimport java.net.*; class UDPServerEx{

public static DatagramSocket mySocket;public static byte myBuffer[]=new byte[2000];public static void serverMethod() throws Exception{

int position=0;while(true){

int charData=System.in.read();switch(charData){

} }

} public static void main(String args[]) throws Exception

System.out.println("Please enter some text here");mySocket=new DatagramSocket(888);serverMethod();

} }



way Communication using Connection-Less Protocol (UDP)

Example : UDPServerEx.Java

//A server that sends a messages to the client

public static DatagramSocket mySocket; myBuffer[]=new byte[2000];

public static void serverMethod() throws Exception{ int position=0;

int charData=System.in.read(); switch(charData){

case -1: System.out.println("The execution of the server has been terminated"); return;

case '\r': break;

case '\n': mySocket.send(new DatagramPacket(myBuffer,position,InetAddress.getLocalHost(),777)); position=0; break;

default: myBuffer[position++]=(byte) charData;

public static void main(String args[]) throws Exception { System.out.println("Please enter some text here"); mySocket=new DatagramSocket(888); serverMethod();

Network Programming

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Less Protocol (UDP)

System.out.println("The execution of the server has been

DatagramPacket(myBuffer,position,InetAddress.getLocalH


Example : UDPClient.Java

//UDPClient - receives and displays messages sent from the serverimport java.net.*; class UDPClient {

public static DatagramSocket mySocket;public static byte myBuffer[]=new byte[2000]; public static void clientMethod() throws Exception

while(true) { DatagramPacket dataPacket=newDatagramPacket(myBuffer,myBuffer.length); mySocket.receive(dataPacket);System System.out.println(newString(dataPacket.getData(),0,dataPacket.getLength()));

} } public static void main(String args[]) throws Exception

System.out.println("You need to press CTRL+C in order to quit");mySocket=newclientMethod();

} }

6. Protocol Handler & Content Handler

When Java Interacts with Network Programming, then it is categorized into two distinct

domains called :

o Protocol Handler

o Content Handler

Protocol Handler is required to take care of certain

on receipt of data, acknowledging that the data has been received

Content Handler is required to :understand

Working of these two categories is totally different and independent. That means

protocol does not care about the type of downloading data.downloaded does not have to worry about the protocol



.Java

receives and displays messages sent from the server

static DatagramSocket mySocket; public static byte myBuffer[]=new byte[2000];

public static void clientMethod() throws Exception {

DatagramPacket dataPacket=new DatagramPacket(myBuffer,myBuffer.length);

mySocket.receive(dataPacket); System.out.println("Message Recieved :");

System.out.println(new String(dataPacket.getData(),0,dataPacket.getLength()));

public static void main(String args[]) throws Exception { System.out.println("You need to press CTRL+C in order to quit");mySocket=new DatagramSocket(777); clientMethod();

& Content Handler


Protocol Handler Content Handler

is required to take care of certain issues: - Generating client requestreceipt of data, acknowledging that the data has been received.

is required to :- Convert the raw data in the format which Java can

wo categories is totally different and independent. That means protocol does not care about the type of downloading data. Similarly data getting downloaded does not have to worry about the protocol.

Network Programming

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String(dataPacket.getData(),0,dataPacket.getLength()));

System.out.println("You need to press CTRL+C in order to quit");


Generating client request,

Convert the raw data in the format which Java can

wo categories is totally different and independent. That means Similarly data getting


Protocol Handler :

Protocol Handler can be defined

protocols. Various protocols supported by JAVA are http,ftp,file.mailto etc. java.net is the package for all this magic. In java.net package there are four important classes defiend

URL – it is the main URLStreamHandler URLConnection

URLStreamHandlerFactory

Content Handler :

What is the Content ? When we request for viewing some file on

then that particular file will be displayed in the browser. Sometimes we can request for viewing some gif and jpg file and the browser displays it. Sometimes we want to see some pdf or ppt file, then browser

external program. Actually the items which get displayed by your browser are reffered to as contents.

Each time when browser wants to handle different contents, plugplug-ins that are required to handle various contenhandler.



Protocol Handler can be defined as a collection of classes which know how to handle

Various protocols supported by JAVA are http,ftp,file.mailto etc. java.net is the package for all this magic. In java.net package there are four important classes defiend

it is the main class URLStreamHandler – it is an abstract class URLConnection – it is an abstract class (getInputStream, getOutputStream)URLStreamHandlerFactory – it is an interface

What is the Content ? When we request for viewing some file on the web browser and if it is a simple HTML file then that particular file will be displayed in the browser. Sometimes we can request for viewing some gif and jpg file and the browser displays it.Sometimes we want to see some pdf or ppt file, then browser

Actually the items which get displayed by your browser are reffered to as contents.

Each time when browser wants to handle different contents, plug-ins that are required to handle various contents on web browser are called content

Network Programming

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as a collection of classes which know how to handle

it is an abstract class (getInputStream, getOutputStream)

the web browser and if it is a simple HTML file

Sometimes we can request for viewing some gif and jpg file and the browser displays it. Sometimes we want to see some pdf or ppt file, then browser takes help of some

Actually the items which get displayed by your browser are reffered to as contents.

-ins are used. These ts on web browser are called content-


1. Explain various types of JDBC drivers and comment on selection of driver.

JDBC Drivers Types:

JDBC driver implementations vary because of the wide variety of operating systems and hardware platforms in which Java operates.

The different types of drivers available in JDBC are listed in following table:

JDBC driver type

Type-1 (JDBC-ODBC Bridge)

Type-2 Driver (Native)

Type-3 Driver (Middleware)

Type-3 Driver (Pure Java)

Type-1 Driver (JDBC-ODBC Bridge) Type-1 driver act as a

JDBC-ODBC bridge driver.

This driver also included in the java2 SDK within the sun.jdbc.odbc package.

This driver converts jdbc calls into odbc calls and redirect the request to odbc driver.

Advantages :

It is represent the single driver

Allow to communicate with all database supported by odbc driver

It is vendor independent driver

Disadvantages:

Decrease the execution speed

Dependent on the odbc driver

Require odbc binary code or odbc client

Uses java native interface to make odbc call

Type-2 Driver (Native) : JDBC call can be converted into the database vendor specific native call with the help of

type-2 driver

Example of type-2 driver is weblogic driver implemented by BEA weblogic

Its not recommended to use type

Unit 2 – JDBC Programming

2160707 – Advanced Java

Explain various types of JDBC drivers and comment on selection

JDBC driver implementations vary because of the wide variety of operating systems and hardware platforms in which Java operates. The different types of drivers available in JDBC are listed in following table:

Description

C Bridge) Refers to the bridge driver(jdbc-odbc diver)

Refers to partly java and partly native code driver(native partly java driver)

(Middleware) Refers to a pure java driver that uses a middleware driver connect to a database(pure java driver for database middleware)

Refers to a pure java driver(pure).which is directly connect to a database

Table 2.1 : JDBC Driver Type

ODBC Bridge) : 1 driver act as a bridge between jdbc and other connecting mechanisms i.e.sun ODBC bridge driver.



It is represent the single driver

Allow to communicate with all database supported by odbc driver

It is vendor independent driver

Decrease the execution speed

Dependent on the odbc driver

Require odbc binary code or odbc client library

Uses java native interface to make odbc call

JDBC call can be converted into the database vendor specific native call with the help of

2 driver is weblogic driver implemented by BEA weblogic

Its not recommended to use type-2 driver with client side application

JDBC Programming

9

Explain various types of JDBC drivers and comment on selection

JDBC driver implementations vary because of the wide variety of operating systems and

The different types of drivers available in JDBC are listed in following table:

odbc diver)

Refers to partly java and partly native code driver(native

Refers to a pure java driver that uses a middleware driver a database(pure java driver for database

Refers to a pure java driver(pure).which is directly

bridge between jdbc and other connecting mechanisms i.e.sun



JDBC call can be converted into the database vendor specific native call with the help of

2 driver is weblogic driver implemented by BEA weblogic

2 driver with client side application


Advantage:

The distinctive characteristic of type 2 jdbc drivers are that they are typically offer better performance than the JDBCthan that of Type 1 and also it uses Native api which is Database specific.

Disadvantage :

Native API must be installed in the Client System and hence type 2 drivers cannot be used for the Internet.

Like Type 1 drivers, it’s not written in Java

If we change the Database we have to change the native api as it is specific to a database.

Mostly obsolete now Usually not thread safe.

Type-3 Driver (Middleware): This driver translate the jdbc calls into a database server independent and middleware

server specific calls.



The distinctive characteristic of type 2 jdbc drivers are that they are typically offer better performance than the JDBC-ODBC Bridge as the layers of communication (tiers) than that of Type 1 and also it uses Native api which is Database specific.

Native API must be installed in the Client System and hence type 2 drivers cannot be used for the Internet.

Like Type 1 drivers, it’s not written in Java Language which forms a portability issue.

If we change the Database we have to change the native api as it is specific to a

Usually not thread safe.

Fig. 2.1 : JDBC Driver Types

(Middleware): driver translate the jdbc calls into a database server independent and middleware

JDBC Programming

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The distinctive characteristic of type 2 jdbc drivers are that they are typically offer better ODBC Bridge as the layers of communication (tiers) are less

than that of Type 1 and also it uses Native api which is Database specific.

Native API must be installed in the Client System and hence type 2 drivers cannot be

Language which forms a portability issue.

If we change the Database we have to change the native api as it is specific to a

driver translate the jdbc calls into a database server independent and middleware


With the help of the middleware server,database server specific calls

This type of driver also

Type-3 driver is recommended to be used with applets.

Advantages:

Serve as all java driver

Does not require any native library to be installed on client machine

Ensure database independency

Does not provide database detail

Provide the facility to switch over from one database to other

Disadvantage:

Its perform the task slowly due to increased number of network calls as compared to type-2 driver

Type-4 Driver (Pure Java): It is pure java driver

This type of driver does not require any native database library to retrieve the record the records from database

This type of driver is lightweight and generally known as thin driver.

You can use this driver when you want an auto doapplication

i.e. thin driver for oracle from oracle corporation, weblogic and ms sqlserver4 for ms sql server from BEA system

Advantages:

Serves as pure java driver

Does not require any native library to install in client

Uses server specific protocol

Does not require middleware server

Disadvantages:

Its uses the database specific proprietary protocol



With the help of the middleware server, the translated jdbc calls further translated into database server specific calls.

This type of driver also known as net-protocol fully java technology-enabled driver

3 driver is recommended to be used with applets. its auto-downloadable

Serve as all java driver

Does not require any native library to be installed on client machine

base independency

Does not provide database detail

Provide the facility to switch over from one database to other

Its perform the task slowly due to increased number of network calls as compared to

(Pure Java):

This type of driver does not require any native database library to retrieve the record the records from database

This type of driver is lightweight and generally known as thin driver.

You can use this driver when you want an auto downloadable option the client side

i.e. thin driver for oracle from oracle corporation, weblogic and ms sqlserver4 for ms sql server from BEA system

Serves as pure java driver

Does not require any native library to install in client machine

Uses server specific protocol

Does not require middleware server

Its uses the database specific proprietary protocol

JDBC Programming

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the translated jdbc calls further translated into

enabled driver.

downloadable.

Its perform the task slowly due to increased number of network calls as compared to

This type of driver does not require any native database library to retrieve the record the

wnloadable option the client side

i.e. thin driver for oracle from oracle corporation, weblogic and ms sqlserver4 for ms sql


2. Explain the use of Statement, PreparedStatement & CallableStatement with example.

Once a connection is

CallableStatement, and PreparedStatement interfaces define the methods and properties that enable you to send SQL or PL/SQL commands and receive data from your database.

They also define methodata types used in a database

Following table provides a summary of each interface's purpose.

Interfaces Recommended Use

Statement Use for generalyou are using static SQL statements at runtime. The Statement interface cannot accept parameters.

PreparedStatement Use when you plan to use the SQL statements many times. The PreparedStatement interface accepts input parameters at runtime.

CallableStatement Use when you want to access database stored procedures. The CallableStatement interface can also accept runtime input parameters.

Statement:

The Statement interface defines a standard abstraction to execute requested by a user and return the results by using the ResultSet object.

The Statement interface is created after the connection to the specified database is made.

The object is created using the createStatement() method of the Connectias shown in following code snippet:

Connection con = DriverManager.getConnection(url, “username”, “password”);Statement stmt = con.createStatement();

Example of Statement import java.io.*; import java.sql.*; class StatementDemo public static void main(String[] args) { try {



in the use of Statement, PreparedStatement & CallableStatement with example.

Once a connection is obtained we can interact with the database. The JDBC Statement, CallableStatement, and PreparedStatement interfaces define the methods and properties that enable you to send SQL or PL/SQL commands and receive data from your

They also define methods that help bridge data type differences between Java and SQL data types used in a database. Following table provides a summary of each interface's purpose.

Recommended Use

Use for general-purpose access to your database. Useful you are using static SQL statements at runtime. The Statement interface cannot accept parameters.

Use when you plan to use the SQL statements many times. The PreparedStatement interface accepts input parameters at runtime.

Use when you want to access database stored procedures. The CallableStatement interface can also accept runtime input parameters.

Table 2.2 : Types of Statements

The Statement interface defines a standard abstraction to execute requested by a user and return the results by using the ResultSet object.

The Statement interface is created after the connection to the specified database is

The object is created using the createStatement() method of the Connectias shown in following code snippet:

Connection con = DriverManager.getConnection(url, “username”, “password”);Statement stmt = con.createStatement();

Example of Statement : Select and Display Record From Table

StatementDemo { public static void main(String[] args) {

JDBC Programming

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in the use of Statement, PreparedStatement &

obtained we can interact with the database. The JDBC Statement, CallableStatement, and PreparedStatement interfaces define the methods and properties that enable you to send SQL or PL/SQL commands and receive data from your

ds that help bridge data type differences between Java and SQL

purpose access to your database. Useful when you are using static SQL statements at runtime. The Statement

Use when you plan to use the SQL statements many times. The PreparedStatement interface accepts input parameters at

Use when you want to access database stored procedures. The CallableStatement interface can also accept runtime input

The Statement interface defines a standard abstraction to execute the SQL statements requested by a user and return the results by using the ResultSet object.

The Statement interface is created after the connection to the specified database is

The object is created using the createStatement() method of the Connection interface,

Connection con = DriverManager.getConnection(url, “username”, “password”);


// Load and register the driver Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

// Establish the connection to the database server Connection cn = DriverManager.getConnection("jdbc:odbc:exm"); // Create a statement Statement st = cn.createStatement(); // Execute the statement ResultSet rs = st.executeQuery("select * from emp // Retrieve the results while(rs.next()) System.out.println(rs.getInt(1)+" "+rs.getString(2)); // Close the statement and connection st.close(); cn.close(); } catch(SQLException e) { System.out.println(e.getMessage()); } } }

PreparedStatement:

The PreparedStatement interface is subclass of the Statement interface,

represent a precompiled query, which can be executed multiple times.

The object is created using the prepareStatement() method of Connection interface, as shown in following snippet:

Connection con = DriverManager.getConnection(url, “usernamString query = “insert into PreparedStatement ps = con.prepareStatement(query);ps.setInt(1,5); ps.setString(2,int n = ps.executeUpdate();

Advantages:

Improves the performance of an application as executes the same query multiple times.

Inserts or updates the SQL 99 data types columns, such as BLOB, CLOB, or OBJECT, with the help of setXXX() methods.

Provides the programmatic approach to set the values.



// Load and register the driver Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

// Establish the connection to the database server Connection cn = DriverManager.getConnection("jdbc:odbc:exm");

// Create a statement Statement st = cn.createStatement();

// Execute the statement ResultSet rs = st.executeQuery("select * from emp”);

// Retrieve the results

System.out.println(rs.getInt(1)+" "+rs.getString(2));

// Close the statement and connection

catch(SQLException e) { System.out.println(e.getMessage());

The PreparedStatement interface is subclass of the Statement interface, represent a precompiled query, which can be executed multiple times.

The object is created using the prepareStatement() method of Connection interface, as shown in following snippet:

Connection con = DriverManager.getConnection(url, “usernamString query = “insert into emp values(? ,?)”; PreparedStatement ps = con.prepareStatement(query);

”New Employee”);

int n = ps.executeUpdate();

Improves the performance of an application as compared to the Statement object that executes the same query multiple times.

Inserts or updates the SQL 99 data types columns, such as BLOB, CLOB, or OBJECT, with the help of setXXX() methods.

Provides the programmatic approach to set the values.

JDBC Programming

13

Connection cn = DriverManager.getConnection("jdbc:odbc:exm");

The PreparedStatement interface is subclass of the Statement interface, can be used to represent a precompiled query, which can be executed multiple times.

The object is created using the prepareStatement() method of Connection interface, as

Connection con = DriverManager.getConnection(url, “username”, “password”);

compared to the Statement object that

Inserts or updates the SQL 99 data types columns, such as BLOB, CLOB, or OBJECT, with


Disadvantages: The main disadvantage of PreparedStatement is that it can represent only one SQL statement at a time.

Example of PreparedStatement

import java.io.*; import java.sql.*; class PreparedStatementDemo public static void main(String[] args) { try { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); String q = "insert into emp(emp_no,emp_name) values (?,?)"; Connection con = DriverManager.getConnection("jdbc:odbc:exm"); PreparedStatement pst = con.prepareStatement(q);

pst.setString(2,"Employee Name"); pst.setInt(1,10); pst.executeUpdate(); pst.setString(2,"New Employee1"); pst.setInt(1,11); pst.executeUpdate(); pst.setString(2,"New Employee2"); pst.setInt(1,12); pst.executeUpdate(); pst.setString(2,"New Employee3"); pst.setInt(1,13); pst.executeUpdate(); pst.setString(2,"New Employee4"); pst.setInt(1,14); pst.executeUpdate(); } catch(Exception e) { System.o } }



The main disadvantage of PreparedStatement is that it can represent only one SQL statement at

Statement : Insert Records into the Table

PreparedStatementDemo { public static void main(String[] args) {

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

String q = "insert into emp(emp_no,emp_name) values (?,?)";

Connection con = DriverManager.getConnection("jdbc:odbc:exm");

nt pst = con.prepareStatement(q);

pst.setString(2,"Employee Name");

pst.executeUpdate();

pst.setString(2,"New Employee1");








catch(Exception e) { System.out.println(e); }

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14

The main disadvantage of PreparedStatement is that it can represent only one SQL statement at

Connection con = DriverManager.getConnection("jdbc:odbc:exm");


CallableStatement: In java the CallableStatement interface is used to call the stored procedure and

functions.

Therefore, the stored procedure can be called by using an object of the CallableStatement interface.

The object is created using the preparein following snippet:

Connection cn = DriverManager.getConnection("jdbc:odbc:exm");CallableStatement cs = cn.prepareCall("{call proc1()}");ResultSet rs= cs.executeQuery();

Example of CallableStatement

import java.io.*; import java.sql.*; class CallableStatement public static void main(String[] args) try { } catch(Exception e) { } } }



In java the CallableStatement interface is used to call the stored procedure and

Therefore, the stored procedure can be called by using an object of the CallableStatement interface.

is created using the prepareCall() method of Connection interface, as shown

Connection cn = DriverManager.getConnection("jdbc:odbc:exm");CallableStatement cs = cn.prepareCall("{call proc1()}"); ResultSet rs= cs.executeQuery();

Statement : Select Records from the Table

CallableStatement { public static void main(String[] args) {

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection cn = DriverManager.getConnection("jdbc:odbc:exm");

//call the procedure CallableStatement cs = cn.prepareCall("{call proc1()}");

//display record selected by the procedure ResultSet rs= cs.executeQuery(); while(rs.next()) System.out.println(rs.getInt(1)+" "+rs.getString(2));

catch(Exception e) { System.out.println(e.getMessage());

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15

In java the CallableStatement interface is used to call the stored procedure and

Therefore, the stored procedure can be called by using an object of the

() method of Connection interface, as shown

Connection cn = DriverManager.getConnection("jdbc:odbc:exm");

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); DriverManager.getConnection("jdbc:odbc:exm");

CallableStatement cs = cn.prepareCall("{call proc1()}");

ln(rs.getInt(1)+" "+rs.getString(2));


3. Explain following in brief: JDBC Architecture

The JDBC API supports both twogeneral JDBC Architecture consists of two layers:

JDBC API: This provides the applicationimportant classes and interface defined in JDBC API are as follows.

o Driver Managero Driver o Connection o Statement o PreparedStatemento CallableStatemento ResultSet o DatabaseMetaDatao ResultSetMetaDatao SqlData o Blob o Clob

JDBC Driver API: This supports the JDBC Manager



Explain following in brief: JDBC Architecture

The JDBC API supports both two-tier and three-tier processing models for database access but in general JDBC Architecture consists of two layers:

This provides the application-to-JDBC Manager connection. Some of the important classes and interface defined in JDBC API are as follows.

Driver Manager

PreparedStatement CallableStatement

DatabaseMetaData ResultSetMetaData

This supports the JDBC Manager-to-Driver Connection.

Fig. 2.2 : JDBC Architecture

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16

database access but in

JDBC Manager connection. Some of the

Driver Connection.


The JDBC API uses a driver manager and

connectivity to heterogeneous databases. The JDBC driver manager ensures that the correct driver is used to access each data

source. The driver manager is capable of supporting multiple concurrent drivers connected to multiple heterogeneous databases.

4. Difference Between executeQuery(), executeUpdate() and execute().

executeQuery() : - executeQuery() can be used to execute selection group sql queries

to fetch the data from database.

public ResultSet executeQuery(String sqlquery) When we use selection group sql query with executeQuery() then JVM will send that sql query to the database engine, database engine will execute it, by this database engine(DBE) will fetch the data from database and send back

executeUpdate() : -to update the database.

public int executeUpdate(String sqlquery) When we provide updation group sql query as a parameter to executeUpdate(), will send that sql query to DBE, here DBE will execute it and perform updations on the database

execute() : - execute() can be used to execute either selection group sql queries or

updation group queries.

public boolean execute(String sqlquery) When we use selection group sql query with the execute() then we will get ResultSet object at heap memory with the fetched data. But execute() will return “true” as a Boolean value. When we use updation group sql query with execute() then we will get “ rcount value” at jdbc application. But execute() will return “false” as a Boolean value.



The JDBC API uses a driver manager and database-specific drivers to provide transparent connectivity to heterogeneous databases. The JDBC driver manager ensures that the correct driver is used to access each data source. The driver manager is capable of supporting multiple concurrent drivers

nnected to multiple heterogeneous databases.

Difference Between executeQuery(), executeUpdate() and

executeQuery() can be used to execute selection group sql queries

to fetch the data from database.

executeQuery(String sqlquery)

When we use selection group sql query with executeQuery() then JVM will send that sql query to the database engine, database engine will execute it, by this database engine(DBE) will fetch the data from database and send back to the java application.

- executeUpdate() can be used to execute updation group sql query

public int executeUpdate(String sqlquery)

When we provide updation group sql query as a parameter to executeUpdate(), will send that sql query to DBE, here DBE will execute it and perform updations on the

execute() can be used to execute either selection group sql queries or

boolean execute(String sqlquery)

When we use selection group sql query with the execute() then we will get ResultSet object at heap memory with the fetched data. But execute() will return “true” as a Boolean value. When we use updation group sql query with execute() then we will get “ rcount value” at jdbc application. But execute() will return “false” as a Boolean value.

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17

specific drivers to provide transparent

The JDBC driver manager ensures that the correct driver is used to access each data source. The driver manager is capable of supporting multiple concurrent drivers

Difference Between executeQuery(), executeUpdate() and

executeQuery() can be used to execute selection group sql queries

When we use selection group sql query with executeQuery() then JVM will send that sql query to the database engine, database engine will execute it, by this database engine(DBE)

executeUpdate() can be used to execute updation group sql query

When we provide updation group sql query as a parameter to executeUpdate(), then JVM will send that sql query to DBE, here DBE will execute it and perform updations on the

execute() can be used to execute either selection group sql queries or

When we use selection group sql query with the execute() then we will get ResultSet object at heap memory with the fetched data. But execute() will return “true” as a Boolean value. When we use updation group sql query with execute() then we will get “ records updated count value” at jdbc application. But execute() will return “false” as a Boolean value.


5. Explain ResultsetMetaData Interface with Example

The metadata means data about data i.e. we can get further information from the data.

If you have to get metadata of a table like total number of column, column name, column type etc. , ResultSetMetaData interface is useful because it provides methods to get metadata from the ResultSet object.

import java.io.*; import java.sql.*; class ResultSetMetaData public static void main(String[] args) { try {

// Load and register the driver try { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); } catch(Exception e) {} //Driver myDriver = new sun.jdbc.odbc.JdbcOdbcDriver(); //DriverManager.registerDriver(myDriver); // Establish the connection to the database server Connection cn = DriverManager.getConnection("jdbc

// Create a statement Statement st = cn.createStatement(); // Execute the statement ResultSet rs = st.executeQuery("select * from emp"); // Create Meta Data object ResultSetMetaData rsmd = rs.getMetaData(); // Get Column Details for(int i=1;i<=rsmd.getColumnCount();i++) System.out.println("Column"+i+" "+rsmd.getColumnName(i)+" "+rsmd.getPrecision(i)+" "+rsmd.getColumnTypeName(i))



Explain ResultsetMetaData Interface with Example


have to get metadata of a table like total number of column, column name, column type etc. , ResultSetMetaData interface is useful because it provides methods to get metadata from the ResultSet object.

{

public static void main(String[] args) {

// Load and register the driver

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

catch(Exception e) {}

//Driver myDriver = new sun.jdbc.odbc.JdbcOdbcDriver(); //DriverManager.registerDriver(myDriver);

// Establish the connection to the database server Connection cn = DriverManager.getConnection("jdbc:odbc:example");

Statement st = cn.createStatement();

// Execute the statement ResultSet rs = st.executeQuery("select * from emp");

// Create Meta Data object ResultSetMetaData rsmd = rs.getMetaData();

for(int i=1;i<=rsmd.getColumnCount();i++) System.out.println("Column"+i+" "+rsmd.getColumnName(i)+"

"+rsmd.getPrecision(i)+" "+rsmd.getColumnTypeName(i));

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18

Explain ResultsetMetaData Interface with Example


have to get metadata of a table like total number of column, column name, column type etc. , ResultSetMetaData interface is useful because it provides methods to get

:odbc:example");

System.out.println("Column"+i+" "+rsmd.getColumnName(i)+"


// Retrieve the results while(rs.next()) System.out.println(rs.getInt("emp_no")+" "+rs.getString(2)); // Close the statement and connection st.close(); cn.close(); } catch(SQLException e) { System.out.println(e.getMessage()); } }

}



// Retrieve the results

System.out.println(rs.getInt("emp_no")+" "+rs.getString(2));

// Close the statement and connection

catch(SQLException e) { System.out.println(e.getMessage());

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19


1. Explain Servlet Life Cycle In the life cycle of servlet there are three important methods.

1. Init() 2. Service() 3. Destroy()

The client enters the URL in the web browser and makes a request. The browser then generates the HTTP request and sends it to the Web server. Web server maps this request to the corresponding servlet. The server basically invokes the servlet is loaded in the memory for the first time. Using this method initialization parameters can also be passed to the servlet in order to configure itself. Server can invoke the service for particular HTcan then read the data provided by the HTTP request with the help of Finally server unloads the servlet from the memory using the

Following is a simple servlet in which used. import javax.servlet.*; import javax.servlet.http.*; import java.io.*; public class LifeCycle extends GenericServlet {public void init(ServletConfig config) throws System.out.println(“init”);}

Unit 3 – Servlet API and Overview


Explain Servlet Life Cycle In the life cycle of servlet there are three important methods. These methods are

Fig. 1 : Servlet Life Cycle enters the URL in the web browser and makes a request. The browser then generates the HTTP request and sends it to the Web server. Web server maps this request to the corresponding servlet.

The server basically invokes the init() method of servlet. This method is called only when the servlet is loaded in the memory for the first time. Using this method initialization parameters can also be passed to the servlet in order to configure itself. Server can invoke the service for particular HTTP request using service() can then read the data provided by the HTTP request with the help of service()Finally server unloads the servlet from the memory using the destroy() method.

Following is a simple servlet in which these three methods viz. init(), service() and destroy() are

class LifeCycle extends GenericServlet { public void init(ServletConfig config) throws ServletException { System.out.println(“init”);

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20

These methods are

enters the URL in the web browser and makes a request. The browser then

of servlet. This method is called only when the servlet is loaded in the memory for the first time. Using this method initialization parameters can method. The servlets service() method.

method. these three methods viz. init(), service() and destroy() are


public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {System.out.println(“from service”);PrintWriter out = response.getWriter();out.println(“welcome to servlet”);out.println(“This is my first servlet”);} public void destroy() { System.out.println(“destroy”);} } ServletContext:

ServletContext object is used to get configuration information from Deployment Descriptor(web.xml) which will be available to any Servlet or JSPs that are part of the web application. There is one context per "web application" per Java Virtual Machine. The ServletContext object is contained within the ServletConfig object. That is, tServletContext can be accessed using the ServletConfig object within a servlet. You can specify paramweb.xml file. Example: <context-param><param-name><param-value></context-param>

Diffrence between ServletContext & ServletConfig.Servlet Config Servlet config object represent single servlet

Its like local parameter associated with particular servlet It’s a name value pair defined inside the servlet section of web.xml file so it has servlet wide scope



public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException { System.out.println(“from service”); PrintWriter out = response.getWriter(); out.println(“welcome to servlet”); out.println(“This is my first servlet”);

public void destroy() { System.out.println(“destroy”);

ServletContext object is used to get configuration information from Deployment Descriptor(web.xml) which will be available to any Servlet or JSPs that are part of the There is one context per "web application" per Java Virtual Machine.The ServletContext object is contained within the ServletConfig object. That is, tServletContext can be accessed using the ServletConfig object within a servlet. You can specify param-value pairs for ServletContext object in <context

param> name>Parameter Name</param-name> value>Parameter Value</param-value> param> Diffrence between ServletContext & ServletConfig.

Servlet Context Servlet config object represent single It represent whole web application running on particular JVM and all the servlet Its like local parameter associated with Its like global parameter associated with whole application It’s a name value pair defined inside the servlet section of web.xml file so it has ServletContext has application wide scope so define outside of servlet tag in web.xml file.

API and Overview

21

public void service(ServletRequest request, ServletResponse response) throws

ServletContext object is used to get configuration information from Deployment Descriptor(web.xml) which will be available to any Servlet or JSPs that are part of the

The ServletContext object is contained within the ServletConfig object. That is, the ServletContext can be accessed using the ServletConfig object within a servlet. value pairs for ServletContext object in <context-param> tags in

It represent whole web application running on particular JVM and common for

Its like global parameter associated with

has application wide scope so define outside of servlet tag in web.xml


getServletConfig() method is used to get the config object for example shopping cart of a user specific to particular user so here we can use servlet config

2. Explain Request Dispatcher The RequestDispatcher interface provides the facility of dispatching the request to another resource it may be html, servlet or jsp. This interface can also be used to include the content of another resource also. It is one of the way of servlet collaboration.

There are two methods defined in the RequestDispatcher interface.1. public void forward(ServletRequest request,ServletResponse response)throws ServletException,java.io.IOException:resource (servlet, JSP file, or2. public void include(ServletRequest request,ServletResponse response)throws ServletException,java.io.IOException:page, or HTML file) in the response.

Example

<form method="post" action="http://localhost:8080/Validate">Name:<input type="text" name="user" /><br/>Password:<input type="password" name="pass" ><br/><input type="submit" value="submit"></form>

import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class Validate extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter();



method is used to get getServletContext() method isthe context object. for example shopping cart of a user is a specific to particular user so here we can To get the MIME type of a file or application session related information is stored using servlet context object.

Request Dispatcher in Java Servlet with example.RequestDispatcher interface provides the facility of dispatching the request to another resource it may be html, servlet or jsp. This interface can also be used to include the content of another resource also. It is one of the way of servlet collaboration.

There are two methods defined in the RequestDispatcher interface. public void forward(ServletRequest request,ServletResponse response)throws ServletException,java.io.IOException: Forwards a request from a servlet to another resource (servlet, JSP file, or HTML file) on the server. public void include(ServletRequest request,ServletResponse response)throws ServletException,java.io.IOException: Includes the content of a resource (servlet, JSP page, or HTML file) in the response.

Index.html method="post" action="http://localhost:8080/Validate"> Name:<input type="text" name="user" /><br/> Password:<input type="password" name="pass" ><br/> <input type="submit" value="submit">

Validate.java

import javax.servlet.http.*; public class Validate extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter();

API and Overview

22

method is used to get To get the MIME type of a file or application session related information is stored using servlet context object.

in Java Servlet with example. RequestDispatcher interface provides the facility of dispatching the request to another resource it may be html, servlet or jsp. This interface can also be used to include the content of another resource also. It is one of the way of servlet collaboration.

public void forward(ServletRequest request,ServletResponse response)throws Forwards a request from a servlet to another public void include(ServletRequest request,ServletResponse response)throws Includes the content of a resource (servlet, JSP

protected void doPost(HttpServletRequest request, HttpServletResponse response)


try { String name = request.getParameter("user"); String password = request.getParameter("pass"); if(password.equals("darshaninst")) { RequestDispatcher rd = request.getRequestDispatcher("Welcome"); rd.forward(request, response); } else { out.println("<font color='red'><b>You have entered incorrect password</b></font>"); } }finally { out.close(); } } }

import java.io.*; import javax.servlet.*; import javax.servlet.http.*;public class Welcome extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); try { out.println("<h2>Welcome user</h2>"); } finally { out.close(); } } }



String name = request.getParameter("user"); String password = request.getParameter("pass"); if(password.equals("darshaninst"))

RequestDispatcher rd = request.getRequestDispatcher("Welcome");rd.forward(request, response);

out.println("<font color='red'><b>You have entered incorrect password</b></font>");

Welcome.java

import javax.servlet.http.*; public class Welcome extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter();

out.println("<h2>Welcome user</h2>");

API and Overview

23

RequestDispatcher rd = request.getRequestDispatcher("Welcome");

out.println("<font color='red'><b>You have entered incorrect password</b></font>");

protected void doPost(HttpServletRequest request, HttpServletResponse response)


<web-app> <servlet> <servlet-name> <servlet-class></servlet> <servlet-mapping> <servlet-name> <url-pattern>/</servlet-mapping> <servlet> <servlet-name> <servlet-class></servlet> <servlet-mapping> <servlet-name> <url-pattern>/</servlet-mapping> </web-app>

3 What is filter? What is its use? List the different filter interfaces with their important methods. A filter is an object that is invoked at the preprocessing and postprocessing of a request.

It is mainly used to perform filtering tasks such as conversion, logging, compression, encryption and decryption, input validation etc. The servlet filter is pluggablethe entry of filter from the web.xml file, filter will be removed automatically and we don't need to change the servlet. So maintenance cost will be less.



web.xml

name>Validate</servlet-name> class>Validate</servlet-class>

name>Validate</servlet-name> pattern>/Validate</url-pattern>

name>Welcome</servlet-name> class>Welcome</servlet-class>

name>Welcome</servlet-name> pattern>/Welcome</url-pattern>

What is filter? What is its use? List the different filter interfaces with their important methods. is an object that is invoked at the preprocessing and postprocessing of a request.

It is mainly used to perform filtering tasks such as conversion, logging, compression, encryption and decryption, input validation etc. servlet filter is pluggable, i.e. its entry is defined in the web.xml file, if we remove the entry of filter from the web.xml file, filter will be removed automatically and we don't need to change the servlet.

So maintenance cost will be less.

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24

What is filter? What is its use? List the different filter interfaces is an object that is invoked at the preprocessing and postprocessing of a request.

It is mainly used to perform filtering tasks such as conversion, logging, compression, . its entry is defined in the web.xml file, if we remove the entry of filter from the web.xml file, filter will be removed automatically and we


Usage of Filter

recording all incoming requests logs the IP addresses of the computers from which the requests originate conversion data compression encryption and decryption input validation etc.

Advantage of Filter Filter is pluggable. One filter don't have dependency Less Maintenance



Fig 1 : Filter

recording all incoming requests logs the IP addresses of the computers from which the requests originate

encryption and decryption

One filter don't have dependency onto another resource.

API and Overview

25

logs the IP addresses of the computers from which the requests originate


Filter API : Like servlet filter have its own API. The javax.servlet package contains the three interfaces of Filter API.

1. Filter 2. FilterChain 3. FilterConfig 1) Filter interface For creating any filter, you must cycle methods for a filter.

Method public void init(FilterConfig config)public void doFilter(HttpServletRequest request,HttpServletResponse response, FilterChain chain) public void destroy()

2) FilterChain interface The object of FilterChain is responsible to invoke the next filter or resource in the chain.This object is passed in the doFilter method of Filter interface.The one method:

1. public void doFilter(HttpServletRequest request, HttpServletResponse response):passes the control to the next filter or resource. Example MyFilter.java import java.io.IOException;import java.io.PrintWriter;import javax.servlet.*; public class MyFilter implementspublic void init(FilterConfig



Like servlet filter have its own API. The javax.servlet package contains the three interfaces of

For creating any filter, you must implement the Filter interface. Filter interface provides the life Description

public void init(FilterConfig config) init() method is invoked only once. It is used to initialize the filter. doFilter(HttpServletRequest request,HttpServletResponse response, doFilter() method is invoked every time when user request to any resource, to which the filter is mapped.It is used to perform filtering tasks.

This is invoked only once when filter is taken out of the service.

The object of FilterChain is responsible to invoke the next filter or resource in the chain.This object is passed in the doFilter method of Filter interface.The FilterChain interface contains only

public void doFilter(HttpServletRequest request, HttpServletResponse response):passes the control to the next filter or resource.

java.io.IOException; java.io.PrintWriter;

implements Filter{ init(FilterConfig arg0) throws ServletException {}

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26

Like servlet filter have its own API. The javax.servlet package contains the three interfaces of

implement the Filter interface. Filter interface provides the life

init() method is invoked only once. It is used to doFilter() method is invoked every time when user request to any resource, to which the filter is mapped.It is used to perform filtering tasks.

is invoked only once when filter is taken out of

The object of FilterChain is responsible to invoke the next filter or resource in the chain.This FilterChain interface contains only

public void doFilter(HttpServletRequest request, HttpServletResponse response): it


public void doFilter(ServletRequestthrows IOException, ServletException PrintWriter out=resp.getWriter();out.print("filterchain.doFilter(req,out.print("filter} public void destroy() {}} HelloServlet.java import java.io.IOException;import java.io.PrintWriter; import javax.servlet.ServletException;import javax.servlet.http.*; public class HelloServlet extends public void doGet(HttpServletRequest throws ServletException, response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.print("<br>welcome } } Web.xml <web-app> <servlet> <servlet-name>s1</servlet<servlet-class>HelloServlet</servlet</servlet> <servlet-mapping> <servlet-name>s1<<url-pattern>/servlet1</url</servlet-mapping>



doFilter(ServletRequest req, ServletResponse resp, FilterChainServletException { out=resp.getWriter(); out.print("filter is invoked before"); chain.doFilter(req, resp);//sends request to next resource out.print("filter is invoked after"); {}

java.io.IOException; java.io.PrintWriter; javax.servlet.ServletException; javax.servlet.http.*;

extends HttpServlet { doGet(HttpServletRequest request, HttpServletResponse response)ServletException, IOException { response.setContentType("text/html"); response.getWriter(); out.print("<br>welcome to servlet<br>");

name>s1</servlet-name> class>HelloServlet</servlet-class>

name>s1</servlet-name> pattern>/servlet1</url-pattern>

API and Overview

27

ilterChain chain)

response)


<filter> <filter-name>f1</filter<filter-class>MyFilter</filter</filter> <filter-mapping> <filter-name>f1</filter<url-pattern>/servlet1<</filter-mapping> </web-app> 4 Explain Request and Response object in servlet. True job of a Servlet is to handle client request.

Servlet API provides two important interfaces javax.servlet.ServletR Implementation of these interfaces provide important information about client request to a servlet.



name>f1</filter-name> class>MyFilter</filter-class>

name>f1</filter-name> pattern>/servlet1</url-pattern>

Explain Request and Response object in servlet. True job of a Servlet is to handle client request. Servlet API provides two important interfaces javax.servlet.ServletRequestjavax.servlet.ServletResponse to encapsulate client request and responseImplementation of these interfaces provide important information about client request

Fig : Servlet Request

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28

javax.servlet.ServletRequest and and response. Implementation of these interfaces provide important information about client request


Index.html <form method="post" action="check">Name <input type="text" name="user" ><input type="submit" value="submit"></form> Web.Xml <servlet> <servlet-name>check</servlet <servlet-class>MyServlet</servlet</servlet> <servlet-mapping> <servlet-name>check</servlet <url-pattern>/check</url</servlet-mapping> MyServlet.java import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class MyServlet extends



Fig : Servlet Response

method="post" action="check"> Name <input type="text" name="user" > <input type="submit" value="submit">

name>check</servlet-name> class>MyServlet</servlet-class>

name>check</servlet-name> pattern>/check</url-pattern>

extends HttpServlet {

API and Overview

29


protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF PrintWriter out = response.getWriter(); try { String user=request.getParameter("user"); out.println("<h2> Welcome "+user+"</h2>"); } finally { out.close(); } } } 5 Session in Servlet, Explain with Example. HTTP is a "stateless" protocol which means each time a client retrieves a Web page, the client opens a separate connection to the Web server and the server automatically does not keep any record of previous client request.

Still there are following three ways to maiserver: Cookies:

o A webserver can assign a unique session ID as a cookie to each web client and for subsequent requests from the client they can be recognized using the recieved cookie. o This may not be an effective cookie, so I would not recommend to use this procedure to maintain the sessions.

Hidden Form Fields: o A web server can send a hidden HTML form field along with a unique session ID as follows: o <input type="ho This entry means that, when the form is submitted, the specified name and value are automatically included in the GET or POST data. Each time when web browser sends request back, then session_id value can be used to kdifferent web browsers.o This could be an effective way of keeping track of the session but clicking on a regular (<A HREF...>) hypertext link does not result in a form submission, so hidden form fields also cannot support general session t



(HttpServletRequest request, HttpServletResponse response)ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); = response.getWriter();

=request.getParameter("user"); out.println("<h2> Welcome "+user+"</h2>");

Session in Servlet, Explain with Example. "stateless" protocol which means each time a client retrieves a Web page, the client opens a separate connection to the Web server and the server automatically does not keep any record of previous client request.

Still there are following three ways to maintain session between web client and web

A webserver can assign a unique session ID as a cookie to each web client and for subsequent requests from the client they can be recognized using the recieved This may not be an effective way because many time browser does not support a cookie, so I would not recommend to use this procedure to maintain the

A web server can send a hidden HTML form field along with a unique session ID <input type="hidden" name="sessionid" value="12345"> This entry means that, when the form is submitted, the specified name and value are automatically included in the GET or POST data. Each time when web browser sends request back, then session_id value can be used to kdifferent web browsers. This could be an effective way of keeping track of the session but clicking on a regular (<A HREF...>) hypertext link does not result in a form submission, so hidden form fields also cannot support general session tracking.

API and Overview

30

(HttpServletRequest request, HttpServletResponse response)

"stateless" protocol which means each time a client retrieves a Web page, the client opens a separate connection to the Web server and the server automatically does ntain session between web client and web

A webserver can assign a unique session ID as a cookie to each web client and for subsequent requests from the client they can be recognized using the recieved way because many time browser does not support a cookie, so I would not recommend to use this procedure to maintain the

A web server can send a hidden HTML form field along with a unique session ID

This entry means that, when the form is submitted, the specified name and value are automatically included in the GET or POST data. Each time when web browser sends request back, then session_id value can be used to keep the track of This could be an effective way of keeping track of the session but clicking on a regular (<A HREF...>) hypertext link does not result in a form submission, so racking.


URL Rewriting: o You can append some extra data on the end of each URL that identifies the session, and the server can associate that session identifier with data it has stored about that session.

Session Tracking Example: // Import required java librariesimport java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.util.*; // Extend HttpServlet class public class SessionTrack extends public void doGet(HttpServletRequest HttpServletResponse throws ServletException { // Create a session object if it is already not created. HttpSession session = request // Get session creation time. Date createTime = new Date // Get last access time of this web page. Date lastAccessTime = new Date(session String title = "Welcome Back to my website" Integer visitCount = new Integer String visitCountKey = new String userIDKey = new String String userID = new String // Check if this is new comer on your web page. if (session.isNew()){ title = "Welcome to my website" session.setAttribute(userIDKey } else { visitCount = (Integer)session visitCount = visitCount + userID = (String)session.getAttribute } session.setAttribute(visitCountKey



You can append some extra data on the end of each URL that identifies the session, and the server can associate that session identifier with data it has stored about that session. Session Tracking Example: java libraries

extends HttpServlet { HttpServletRequest request, HttpServletResponse response) ServletException, IOException

// Create a session object if it is already not created. request.getSession(true); // Get session creation time. Date(session.getCreationTime()); // Get last access time of this web page. session.getLastAccessedTime());

"Welcome Back to my website"; Integer(0); new String("visitCount"); String("userID"); String("ABCD"); // Check if this is new comer on your web page.

"Welcome to my website"; userIDKey, userID); session.getAttribute(visitCountKey); + 1; getAttribute(userIDKey);

visitCountKey, visitCount);

API and Overview

31

You can append some extra data on the end of each URL that identifies the session, and the server can associate that session identifier with data it has


// Set response content type response.setContentType( PrintWriter out = response String docType = "<!doctype html public \"- "transitional//en\">\n"; out.println(docType + "<html>\n" + "<head><title>" + title "<body bgcolor=\"#f0f0f0 "<h1 align=\"center\ "<h2 align=\"center "<table border=\"1\" align= "<tr bgcolor=\"#949494 " <th>Session info</th><th>value</th></tr> "<tr>\n" + " <td>id</td>\n" + " <td>" + session.getId "<tr>\n" + " <td>Creation Time</td> " <td>" + createTime " </td></tr>\n" + "<tr>\n" + " <td>Time of Last Access</td> " <td>" + lastAccessTime " </td></tr>\n" + "<tr>\n" + " <td>User ID</td>\ " <td>" + userID + " </td></tr>\n" + "<tr>\n" + " <td>Number of visits</td> " <td>" + visitCount "</table>\n" + "</body></html>"); } }



// Set response content type ("text/html"); response.getWriter();

-//w3c//dtd html 4.0 " +

title + "</title></head>\n" + "#f0f0f0\">\n" + \">" + title + "</h1>\n" + "center\">Session Infomation</h2>\n" + " align=\"center\">\n" + "#949494\">\n" + </th><th>value</th></tr>\n" + getId() + "</td></tr>\n" +

" <td>Creation Time</td>\n" + createTime +

" <td>Time of Last Access</td>\n" + lastAccessTime +

\n" +

" <td>Number of visits</td>\n" + visitCount + "</td></tr>\n" +

API and Overview

32


1. Explain JSP unified Expression Language (EL) .

EL is a language that allows JSP programmers to fetch application data stored in JavaBeans

component.

The following methods are used to 1. Placing the entire Java code in a JSP page2. Defining separate helper classes that encapsulate the entire Java code and calling

these helper classes from a JSP page3. Using JavaBeans and JSP page action tags4. Using JSP EL 5. Create tag handler classes to embed the Java code

The incorporation of EL to the JSP has helped reduce the use of scriptles in JSP page.

EL expressions provide short hand notations to retrieve, present, and manipulate Web application data.

EL expressions are enclosed between the ${ and} characters.

The most general example of an EL expression is ${object.data}Where, object can be any Java object representing different scope, such as request,session.

EL expressiongs can be categorized into the following ty1. Immediate and deferred expressions2. Value expressions3. Method expressions

1) Immediate and deferred expressions

Two constructs are used to represent EL expressions, ${ expr } used for expressions that need to be evaluated immediately, and #{ expr } used for expressions that need to be evaluated at later time.

An expression that uses ${ expr } is called immediate expression and

The expression that uses #{ expr } is called deferred expression.2) Value Expressions

Value epressions are used to refer to objects enumerations and implicit objects and their properties.

An object is referred to by using the value expression containing the name of the object

Suppose the ${ employee } expression is used in a JSP page, where employee refethe name of a JavaBean.

Which searches for the employee JavaBeab in the request, session and application scopes

If the employee JavaBean does not exist, a null value is returned.

Syntax of value expression to access properties and elements of a colletwo operators, ( . ) and ( [] ).

For example, The name property of the employee JavaBean can be referred as

${employee.name} or ${ employee[“name”] } expression.

Unit 4 – Java

| 2160707– Advanced Java

Explain JSP unified Expression Language (EL) .


The following methods are used to call the java code from a JSP page: Placing the entire Java code in a JSP page

Defining separate helper classes that encapsulate the entire Java code and calling these helper classes from a JSP page Using JavaBeans and JSP page action tags

Create tag handler classes to embed the Java code


EL expressions provide short hand notations to retrieve, present, and manipulate Web

re enclosed between the ${ and} characters.

The most general example of an EL expression is ${object.data} Where, object can be any Java object representing different scope, such as

EL expressiongs can be categorized into the following types: Immediate and deferred expressions Value expressions Method expressions

Immediate and deferred expressions

Two constructs are used to represent EL expressions, ${ expr } used for expressions that need to be evaluated immediately, and

for expressions that need to be evaluated at later time.

An expression that uses ${ expr } is called immediate expression and

The expression that uses #{ expr } is called deferred expression.

Value epressions are used to refer to objects such as JavaBeans, Collections, enumerations and implicit objects and their properties.


Suppose the ${ employee } expression is used in a JSP page, where employee refethe name of a JavaBean.

Which searches for the employee JavaBeab in the request, session and application

If the employee JavaBean does not exist, a null value is returned.

Syntax of value expression to access properties and elements of a colletwo operators, ( . ) and ( [] ).

The name property of the employee JavaBean can be referred as ${employee.name} or ${ employee[“name”] } expression.

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Defining separate helper classes that encapsulate the entire Java code and calling


EL expressions provide short hand notations to retrieve, present, and manipulate Web

Where, object can be any Java object representing different scope, such as

${ expr } used for expressions that need to be evaluated immediately, and for expressions that need to be evaluated at later time.

such as JavaBeans, Collections,


Suppose the ${ employee } expression is used in a JSP page, where employee refers to

Which searches for the employee JavaBeab in the request, session and application

Syntax of value expression to access properties and elements of a collection in java uses

The name property of the employee JavaBean can be referred as


To access a specific element of a collection, such as list or an array insiJavaBean we can use ${ employee.name[0] }, ${ employee.name[1] }, etc…

The value expressions are of two types:o rvalue

rvalue expression can only read data, and not write data.o lvalue

lvalue expression can read as well as write data.3) Method Expressions

Method expressions are used to call public methods, which returns a value or object.

Such expressions are usually deferred expressions.

Tags usually use method expressions to call functions that perform operations such as validating a UI component or hand

The following code snippet shows the use of method expressions in JSF page: <h:form>

<h:inputText id=”email”value=”#{employee.email}validator=”#{employee.validateEmail}” />

<h:commandButton id=”submit”action=”#{customer.submit}” />

</h:form>

The various elements shown in the preceding code snippet can be briefly described as follows: o The inputText tag : shows the UIInput component in the form of a text field on a

webpage o The validator attribute : callso The action attribute of the

carries out processing after submitting the webpageo The validateEmail method : Refers to the method that is called during the

phase of the JSP life cycleo The submit method : Refers to the method that is called during the invoke application

phase of the JSP life cycle

Unit 4 – Java


To access a specific element of a collection, such as list or an array insiJavaBean we can use ${ employee.name[0] }, ${ employee.name[1] }, etc…

The value expressions are of two types:

rvalue expression can only read data, and not write data.

lvalue expression can read as well as write data.


Such expressions are usually deferred expressions.

Tags usually use method expressions to call functions that perform operations such as validating a UI component or handling the events generated on a UI component.

The following code snippet shows the use of method expressions in JSF page:

id=”email” value=”#{employee.email} validator=”#{employee.validateEmail}” />

id=”submit” action=”#{customer.submit}” />

The various elements shown in the preceding code snippet can be briefly described as

tag : shows the UIInput component in the form of a text field on a

attribute : calls the validateEmail method of the employee JavaBeanattribute of the commandButton tag : calls the submit method, which

carries out processing after submitting the webpage method : Refers to the method that is called during the

phase of the JSP life cycle method : Refers to the method that is called during the invoke application

phase of the JSP life cycle

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To access a specific element of a collection, such as list or an array inside a JavaBean we can use ${ employee.name[0] }, ${ employee.name[1] }, etc…


Tags usually use method expressions to call functions that perform operations such as ling the events generated on a UI component.

The following code snippet shows the use of method expressions in JSF page:

The various elements shown in the preceding code snippet can be briefly described as

tag : shows the UIInput component in the form of a text field on a

the validateEmail method of the employee JavaBean tag : calls the submit method, which

method : Refers to the method that is called during the validation

method : Refers to the method that is called during the invoke application


2 Enlist and explain the use of action tags in JSP.

Action tags are specific to a JSP page. When a translating a JSP page into a servlet, it generates a Java code corresponding to the task to be performed by the action tag.

The following are some important action tags available in JSP page:1. <jsp:include>

o The <jsp:include> action tag facilitates Java programmers in including a static or dynamic resource, such as an HTML or JSP page in the current JSP page.

o If the resource to be included is static then its content is directly included.o If the resource is dyno Example

<jsp:include page=”test.jsp” />2. <jsp:forward>

o The <jsp:forward> tag forwards a JSP request to another resource which can be either static or dynamic.

o If the request is forwarded to a pass a name and value of a parameter to a resource.

o Example: <jsp:forward page=”/header.html” />

3. <jsp:param> o The <jsp:param> tag allows Java programmers to pass a name and value of a

parameter to a dynamicrequest to another JSP page.

o Example: <jsp:param name=”uname” value=”

4. <jsp:useBean> o To separate the business logic from the presentation logic, it is often a good idea to

encapsulate the busiobject within a JSP page, <jsp:useBean> tag helps in such task.

o The <jsp:useBean> action tag has certain attributes that add extra characteristics to it, some attributes specific to <jsp:use

Id : represents the name assigned to a JavaBean, which is later used as a variable to access the JavaBean

Class : takes the qualified class name to create a JavaBean instance if the JavaBean instance is not found in the given scope.

beanNameo takes the qualified class name or expression of a JavaBean to create a

JavaBean. o Class & beanName can not be used together.o We can not use expressions to create instance of JavaBean from class

attribute, for that we have to use beanName attribute.

Unit 4 – Java


Enlist and explain the use of action tags in JSP.

Action tags are specific to a JSP page. When a JSP container encounters an action tag while translating a JSP page into a servlet, it generates a Java code corresponding to the task to be performed by the action tag. The following are some important action tags available in JSP page:

The <jsp:include> action tag facilitates Java programmers in including a static or dynamic resource, such as an HTML or JSP page in the current JSP page.If the resource to be included is static then its content is directly included.If the resource is dynamic then first it is processed and result is included in page.

<jsp:include page=”test.jsp” />

The <jsp:forward> tag forwards a JSP request to another resource which can be either static or dynamic. If the request is forwarded to a dynamic resource, a <jsp:param> tag can be used to pass a name and value of a parameter to a resource.

<jsp:forward page=”/header.html” />

The <jsp:param> tag allows Java programmers to pass a name and value of a parameter to a dynamic resource, while including it in a JSP page or forwarding a request to another JSP page.

<jsp:param name=”uname” value=”PM”/>

e business logic from the presentation logic, it is often a good idea to encapsulate the business login in Java object, and then instantiate and use this Java object within a JSP page, <jsp:useBean> tag helps in such task. The <jsp:useBean> action tag has certain attributes that add extra characteristics to it, some attributes specific to <jsp:useBean> are:

: represents the name assigned to a JavaBean, which is later used as a variable to access the JavaBean

: takes the qualified class name to create a JavaBean instance if the JavaBean instance is not found in the given scope. beanName :

takes the qualified class name or expression of a JavaBean to create a JavaBean. Class & beanName can not be used together. We can not use expressions to create instance of JavaBean from class attribute, for that we have to use beanName attribute.

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JSP container encounters an action tag while translating a JSP page into a servlet, it generates a Java code corresponding to the task to be

The <jsp:include> action tag facilitates Java programmers in including a static or dynamic resource, such as an HTML or JSP page in the current JSP page. If the resource to be included is static then its content is directly included.

amic then first it is processed and result is included in page.

The <jsp:forward> tag forwards a JSP request to another resource which can be

dynamic resource, a <jsp:param> tag can be used to

The <jsp:param> tag allows Java programmers to pass a name and value of a resource, while including it in a JSP page or forwarding a

e business logic from the presentation logic, it is often a good idea to ness login in Java object, and then instantiate and use this Java

The <jsp:useBean> action tag has certain attributes that add extra characteristics to

: represents the name assigned to a JavaBean, which is later used as a

: takes the qualified class name to create a JavaBean instance if the

takes the qualified class name or expression of a JavaBean to create a

We can not use expressions to create instance of JavaBean from class attribute, for that we have to use beanName attribute.


Scope : represents the scope in which a JavaBean instance has to be created.o Page scope

<jsp:useBean> action tag is used.o Request scope

page, which processes the saclient by the JSP page.

o Session scopepage invoked in the same session as the JSP page that created the JavaBean.

o Application scopeJSP page in the same application as the JSP page that created the JavaBean.

o Example : <jsp:useBean id=”myBean” class=”MyBeanClass” scope=”session”> ………….</jsp:useBean>

5. <jsp:setProperty> o The <jsp:setProperty> action tag sets

method of a JavaBean.o Before using the <jsp:setProperty> action tag, the JavaBean must be instantiated.o Example:

<jsp:setProperty name=”beanName” property=”uName” value=”6. <jsp:getProperty>

o The <jsp:setPropmethod of a JavaBean and writes the value of the current JspWriter.

o Example: <jsp:getProperty name=”myBean” property=”uName” />

7. <jsp:plugin> o The <jsp:plugin> action tag provides support

in a client Web browser, by using builto The <jsp:plugin> action tag perform the following operations:

Specify whether the component added in the <object> tag is a JavaBean or an applet.

Locate the code that needs to be run. Position an object in the browser window. Specify a URL from which the plug Pass parameter names and values to an object

o Example: <jsp:plugin attributes> ………. </jsp:plugin>

8. <jsp:params> o The <jsp:params> action tag sends the parameters that you want to pass to an

Unit 4 – Java


represents the scope in which a JavaBean instance has to be created.Page scope : indicates that a JavaBean can be used where <jsp:useBean> action tag is used. Request scope : indicates that a JavaBean can be used from any JSP page, which processes the same request until a response is sent to a client by the JSP page. Session scope : indicates that a JavaBean can be used from any JSP page invoked in the same session as the JSP page that created the JavaBean. Application scope : indicates that a JavaBean caJSP page in the same application as the JSP page that created the JavaBean.

<jsp:useBean id=”myBean” class=”MyBeanClass” scope=”session”>………….

</jsp:useBean>

The <jsp:setProperty> action tag sets the value of a property by using the setter method of a JavaBean. Before using the <jsp:setProperty> action tag, the JavaBean must be instantiated.

<jsp:setProperty name=”beanName” property=”uName” value=”

The <jsp:setProperty> action tag retrives the value of a property by using the getter method of a JavaBean and writes the value of the current JspWriter.

<jsp:getProperty name=”myBean” property=”uName” />

The <jsp:plugin> action tag provides support for including a Java applet or JavaBean in a client Web browser, by using built-in or downloaded Java plugThe <jsp:plugin> action tag perform the following operations:

Specify whether the component added in the <object> tag is a JavaBean or an

Locate the code that needs to be run. Position an object in the browser window. Specify a URL from which the plug-in software is to be downloaded.Pass parameter names and values to an object

<jsp:plugin attributes>

</jsp:plugin>

The <jsp:params> action tag sends the parameters that you want to pass to an

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represents the scope in which a JavaBean instance has to be created. : indicates that a JavaBean can be used where

: indicates that a JavaBean can be used from any JSP me request until a response is sent to a

: indicates that a JavaBean can be used from any JSP page invoked in the same session as the JSP page that created the

: indicates that a JavaBean can be used from any JSP page in the same application as the JSP page that created the

<jsp:useBean id=”myBean” class=”MyBeanClass” scope=”session”>

the value of a property by using the setter

Before using the <jsp:setProperty> action tag, the JavaBean must be instantiated.

<jsp:setProperty name=”beanName” property=”uName” value=”PM” />

erty> action tag retrives the value of a property by using the getter method of a JavaBean and writes the value of the current JspWriter.

for including a Java applet or JavaBean in or downloaded Java plug-in.

Specify whether the component added in the <object> tag is a JavaBean or an

in software is to be downloaded.

The <jsp:params> action tag sends the parameters that you want to pass to an


applet or JavaBean.o Example:

<jsp:params><!- one or more jsp:param tags

</jsp:params>9. <jsp:fallback>

o The <jsp:fallback> action tag is allows you to specify a text displayed if the required plug

o This tag must be used as a child tag with <jsp:plugin> action tag.o Example:

<jsp:fallback>Text message that has to be displayed if the plugin cannot be started

</jsp:fallback>10. <jsp:attribute>

o The <jsp:attribute> action tag is used to specify the value of a standard or custom action attribute.

o Example: <jsp:setProperty name=”myBean”>

<jsp:attribute name=”property”>uName</jsp:attribute><jsp:attribute name=”value”>

</jsp:setProperty>11. <jsp:body>

o The <jsp:body> action tag is used to specify the content (or body) of a standard or custom action tag.

o Example: <jsp:userBean id=”myBean”>

…….. <jsp:body> ……………. </jsp:body>

</jsp:myBean>12. <jsp:element>

o The <jsp:element> actian XML element.

o Example: <jsp:element name=”mytag”>

<jsp:attribute name=”myatt”>My Value </jsp:attribute></jsp:element>

13. <jsp:text> o A <jsp:text> tag is used to enclose template data in an XML o The content of the <jsp:text> body is passed to the implicit object o Example:

<jsp:text> Hello world from the action tag </jsp:text>

Unit 4 – Java


applet or JavaBean.

<jsp:params> one or more jsp:param tags -->

</jsp:params>

The <jsp:fallback> action tag is allows you to specify a text displayed if the required plug-in cannot run. This tag must be used as a child tag with <jsp:plugin> action tag.

<jsp:fallback> Text message that has to be displayed if the plugin cannot be started

</jsp:fallback>

he <jsp:attribute> action tag is used to specify the value of a standard or custom

<jsp:setProperty name=”myBean”> <jsp:attribute name=”property”>uName</jsp:attribute><jsp:attribute name=”value”>PM</jsp:attribute>

/jsp:setProperty>

The <jsp:body> action tag is used to specify the content (or body) of a standard or custom action tag.

<jsp:userBean id=”myBean”>

<jsp:body> ……………. </jsp:body> </jsp:myBean>

The <jsp:element> action tag is used to dynamically define the value of the tag of an XML element.

<jsp:element name=”mytag”> <jsp:attribute name=”myatt”>My Value </jsp:attribute>

</jsp:element>

A <jsp:text> tag is used to enclose template data in an XML tag.The content of the <jsp:text> body is passed to the implicit object

<jsp:text> Hello world from the action tag </jsp:text>

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The <jsp:fallback> action tag is allows you to specify a text message that is

This tag must be used as a child tag with <jsp:plugin> action tag.

Text message that has to be displayed if the plugin cannot be started

he <jsp:attribute> action tag is used to specify the value of a standard or custom

<jsp:attribute name=”property”>uName</jsp:attribute>

The <jsp:body> action tag is used to specify the content (or body) of a standard or

on tag is used to dynamically define the value of the tag of

<jsp:attribute name=”myatt”>My Value </jsp:attribute>

tag. The content of the <jsp:text> body is passed to the implicit object out.


3 Explain JSP standard tag library (JSTL) with examples.

Initially, web designers used scriplets in JSP pages

This resulted in readability issues and also made it difficult to maintain the JSP page.

Custom tags were introduced to overcome the problems faced in using scriplets, they had some limitations too.

Web designers had to spend ausing them.

This meant that web designers were often left with little time to concentrate on the designing of web pages.

The introduction of JSTL has helped web designers overcome the shortcotags, by encapsulating the common functionalities included the use of tag libraries, such as core, SQL, and XML.

The main features of JSTL are:o Provides support for conditional processing and Uniform Resource Locator (URL)

related actions. o Provides the XML tag library, which helps you to manipulate XML documents.o Enables Web applications to be accessed globally by providing the

internationalization tag library.o Enables interaction with relational databases by using various SQL commands.o Provides series of functions to perform manipulations.

Tag Libraries in JSTL:

Tag Library Function

Core tag library Variable support

Flow Control

Iterator

URL management

Miscellaneous

XML tag library Flow control

Transformation

Locale

Internationalizatio

n tag library

Message

formatting

Number and date

formatting

SQL tag library Database

manipulation

Unit 4 – Java


Explain JSP standard tag library (JSTL) with examples.

Initially, web designers used scriplets in JSP pages to generate dynamic content.

bility issues and also made it difficult to maintain the JSP page.

Custom tags were introduced to overcome the problems faced in using scriplets, they had

Web designers had to spend a lot of time in coding, packaging, and testing these tags before

This meant that web designers were often left with little time to concentrate on the

The introduction of JSTL has helped web designers overcome the shortcotags, by encapsulating the common functionalities included the use of tag libraries, such as

The main features of JSTL are: Provides support for conditional processing and Uniform Resource Locator (URL)

Provides the XML tag library, which helps you to manipulate XML documents.Enables Web applications to be accessed globally by providing the internationalization tag library. Enables interaction with relational databases by using various SQL commands.

ides series of functions to perform manipulations.

Function URI

Variable support

Flow Control

Iterator

URL management

Miscellaneous

http://java.sun.com/jsp/jstl/core

control

Transformation

Locale

http://java.sun.com/jsp/jstl/xml

Message

formatting

Number and date

formatting

http://java.sun.com/jsp/jstl/fmt

Database

manipulation

http://java.sun.com/jsp/jstl/sql

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Explain JSP standard tag library (JSTL) with examples.

to generate dynamic content.

bility issues and also made it difficult to maintain the JSP page.

Custom tags were introduced to overcome the problems faced in using scriplets, they had

lot of time in coding, packaging, and testing these tags before

This meant that web designers were often left with little time to concentrate on the

The introduction of JSTL has helped web designers overcome the shortcomings of custom tags, by encapsulating the common functionalities included the use of tag libraries, such as

Provides support for conditional processing and Uniform Resource Locator (URL)-

Provides the XML tag library, which helps you to manipulate XML documents. Enables Web applications to be accessed globally by providing the

Enables interaction with relational databases by using various SQL commands.

prefix

http://java.sun.com/jsp/jstl/core c

http://java.sun.com/jsp/jstl/xml x

fmt

sql


Functions Library Collection length

String

manipulation

Example of Core tag library:<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><html> <head> <title><c:choose> Tag Example</title></head> <body> <c:set var="salary" scope="session" value="${2000*2}"/><p>Your salary is : <c:out value="${salary}"/></p><c:choose> <c:when test="${salary <= 0}"> Salary is very low to survive. </c:when> <c:when test="${salary > 1000}"> Salary is very good. </c:when> <c:otherwise> No comment... </c:otherwise> </c:choose> </body> </html>

4 What is XML tag library? Explain the XML core tags and show their use.

The JSTL XML tags provide a JSP

Following is the syntax to include JSTL XML library in your JSP.

The JSTL XML tag library has custom tags for interacting with XML data. This includes parsing XML, transforming XML

<%@ taglib prefix="x" uri="http://java.sun.com/jsp/jstl/xml" %>

Before you proceed with the examples, you would need to copy following two XML and

XPath related libraries into your <Tomcat

Unit 4 – Java


Collection length

manipulation

http://java.sun.com/jsp/jstl/functi

ons

Example of Core tag library: <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

<c:choose> Tag Example</title>

<c:set var="salary" scope="session" value="${2000*2}"/> <p>Your salary is : <c:out value="${salary}"/></p>

<c:when test="${salary <= 0}"> Salary is very low to survive.

c:when test="${salary > 1000}">

What is XML tag library? Explain the XML core tags and show

tags provide a JSP-centric way of creating and manipulating XML documents. Following is the syntax to include JSTL XML library in your JSP.

The JSTL XML tag library has custom tags for interacting with XML data. This includes parsing XML, transforming XML data, and flow control based on XPath expressions.

uri="http://java.sun.com/jsp/jstl/xml" %>

Before you proceed with the examples, you would need to copy following two XML and XPath related libraries into your <Tomcat Installation Directory>\lib:

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http://java.sun.com/jsp/jstl/functi fn

What is XML tag library? Explain the XML core tags and show

centric way of creating and manipulating XML documents.

The JSTL XML tag library has custom tags for interacting with XML data. This includes data, and flow control based on XPath expressions.

Before you proceed with the examples, you would need to copy following two XML and


XercesImpl.jar: Download it from xalan.jar: Download it from

Following is the list of XML JSTL Tags:

Tag

<x:out> Like <%= ... >, but for XPath expressions.

<x:parse> Use to parse XML data specified either via an attribute or in the tag body.

<x:set > Sets a variable to the

<x:if >

Evaluates a test XPath expression and if it is true, it processes its body. If the test condition is false, the body is ignored.

<x:forEach> To loop over nodes in an XML document.

<x:choose>

Simple conditional tag that establishes a context conditional operations, marked by <when> and <otherwise>

<x:when > Subtag of <choose> that includes its body if its expression evalutes to 'true'

<x:otherwise >

Subtag of <choose> that follows <when> tags and runs only if all of the prior conditions evaluated to 'false'

<x:transform > Applies an XSL transformation on a XML document

<x:param > Use along with the transform tag to set a parameter in the XSLT stylesheet

5 Explain SQL Tab Libraries

The JSTL SQL tag library provides tags for interacting with relational databases (RDBMSs) such as Oracle, mySQL, or Microsoft SQL Server.

Following is the syntax to include JSTL SQL library in your JSP:<%@ taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql" %>

Following is the list of SQL JSTL Tags:

Tag Description

<sql:setDataSource> Creates a simple DataSource suitable only for

<sql:query> Executes the SQL query defined in its body or through the sql attribute.

<sql:update> Executes the SQL update defined in its body or through the sql attribute.

<sql:param> Sets a parameter in an SQL statement to the specified value.

<sql:dateParam> Sets a parameter in an SQL statement to the specified java.util.Date

<sql:transaction > Provides nested database action

Unit 4 – Java


Download it from http://www.apache.org/dist/xerces/j/Download it from http://xml.apache.org/xalan-j/index.html

Following is the list of XML JSTL Tags:

Description

Like <%= ... >, but for XPath expressions.

Use to parse XML data specified either via an attribute or in the tag body.

Sets a variable to the value of an XPath expression.

Evaluates a test XPath expression and if it is true, it processes its body. If the test condition is false, the body is ignored.

To loop over nodes in an XML document.

Simple conditional tag that establishes a context for mutually exclusive conditional operations, marked by <when> and <otherwise>

Subtag of <choose> that includes its body if its expression evalutes to 'true'

Subtag of <choose> that follows <when> tags and runs only if all of the prior conditions evaluated to 'false'

Applies an XSL transformation on a XML document

Use along with the transform tag to set a parameter in the XSLT stylesheet

Libraries.

The JSTL SQL tag library provides tags for interacting with relational databases (RDBMSs) such as Oracle, mySQL, or Microsoft SQL Server. Following is the syntax to include JSTL SQL library in your JSP:

i="http://java.sun.com/jsp/jstl/sql" %>

Following is the list of SQL JSTL Tags:

Description

Creates a simple DataSource suitable only for prototyping

Executes the SQL query defined in its body or through the sql attribute.

Executes the SQL update defined in its body or through the sql attribute.

Sets a parameter in an SQL statement to the specified value.

Sets a parameter in an SQL statement to the specified java.util.Date

Provides nested database action elements with a shared Connection

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http://www.apache.org/dist/xerces/j/ j/index.html

Use to parse XML data specified either via an attribute or in the tag body.

Evaluates a test XPath expression and if it is true, it processes its body. If the

for mutually exclusive conditional operations, marked by <when> and <otherwise>

Subtag of <choose> that includes its body if its expression evalutes to 'true'

Subtag of <choose> that follows <when> tags and runs only if all of the prior

Use along with the transform tag to set a parameter in the XSLT stylesheet

The JSTL SQL tag library provides tags for interacting with relational databases (RDBMSs)

prototyping

Executes the SQL query defined in its body or through the sql attribute.

Executes the SQL update defined in its body or through the sql attribute.

Sets a parameter in an SQL statement to the specified value.

Sets a parameter in an SQL statement to the specified java.util.Date

elements with a shared Connection.


6 Explain Core JSTL Tags

The core group of tags are the most frequently used JSTL tags. Following is the syntax to include JSTL Core library in your JSP:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

There are following Core JSTL Tags:

Tag

<c:out > Like <%= ... >, but for expressions.

<c:set > Sets the result of an expression evaluation in a 'scope'

<c:remove > Removes a scoped variable (from a pa

<c:catch> Catches any Throwable that occurs in its body and optionally exposes it.

<c:if> Simple conditional tag which evalutes its body if the supplied condition is true.

<c:choose>

Simple conditional tag that establishes a context for mutually exclusive conditional operations, marked by <when> and <otherwise>

<c:when> Subtag of <choose> that includes its body if its condition evalutes to 'true'.

<c:otherwise >

Subtag of <choose> that follows <when> tags and runs only if all of the prior conditions evaluated to 'false'.

<c:import>

Retrieves an absolute or relative URL and exposes its contents to either the page, a String in 'var', or a Reader in 'varReader'.

<c:forEach >

The basic iteration tag, accepting many different collection types and supporting subsetting and other functionality .

<c:forTokens> Iterates over tokens, separated by the supplied delimeters.

<c:param> Adds a parameter to a containing 'import' tag's URL.

<c:redirect > Redirects to a new URL.

<c:url> Creates a URL with optional query parameters

7 Explain Session Handling with example.

HTTP is a "stateless" protocol which means each time a client retrieves a Web page, client opens a separate connection to the Web server and the server automatically does not keep any record of previous client request.


server:

Unit 4 – Java


Explain Core JSTL Tags

The core group of tags are the most frequently used JSTL tags. Following is the syntax to include JSTL Core library in your JSP: <%@ taglib prefix="c"

uri="http://java.sun.com/jsp/jstl/core" %>

There are following Core JSTL Tags:

Description

Like <%= ... >, but for expressions.

Sets the result of an expression evaluation in a 'scope'

Removes a scoped variable (from a particular scope, if specified).

Catches any Throwable that occurs in its body and optionally exposes it.

Simple conditional tag which evalutes its body if the supplied condition is true.

Simple conditional tag that establishes a context for mutually exclusive onal operations, marked by <when> and <otherwise>

Subtag of <choose> that includes its body if its condition evalutes to 'true'.

Subtag of <choose> that follows <when> tags and runs only if all of the prior conditions evaluated to 'false'.

Retrieves an absolute or relative URL and exposes its contents to either the page, a String in 'var', or a Reader in 'varReader'.

eration tag, accepting many different collection types and supporting subsetting and other functionality .

Iterates over tokens, separated by the supplied delimeters.

Adds a parameter to a containing 'import' tag's URL.

Redirects to a new URL.

Creates a URL with optional query parameters

Explain Session Handling with example.

HTTP is a "stateless" protocol which means each time a client retrieves a Web page, client opens a separate connection to the Web server and the server automatically does not keep any record of previous client request. Still there are following three ways to maintain session between web client and web

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The core group of tags are the most frequently used JSTL tags. Following is the syntax to

rticular scope, if specified).

Catches any Throwable that occurs in its body and optionally exposes it.

Simple conditional tag which evalutes its body if the supplied condition is true.

Simple conditional tag that establishes a context for mutually exclusive onal operations, marked by <when> and <otherwise>

Subtag of <choose> that includes its body if its condition evalutes to 'true'.

Subtag of <choose> that follows <when> tags and runs only if all of the prior

Retrieves an absolute or relative URL and exposes its contents to either the

eration tag, accepting many different collection types and supporting

HTTP is a "stateless" protocol which means each time a client retrieves a Web page, the client opens a separate connection to the Web server and the server automatically does



Cookies:

A webserver can assign a unique session ID as a cookie to each web client and for

subsequent requests from the client they can be recognized using the received cookie.

This may not be an effective way because many time browser does not support a cookie, so I would not recommend to use this procedure to maintain the sessions.

Hidden Form Fields:

A web server can send a hidden HTML form field along with a unique session ID as follows:

<input type="hidden"

This entry means that, when the form is submitted, the specified name and value are automatically included in the GET or POST data. Each time when web browser sends request back, then session_id value can be used to keep the track of different web browsers.

This could be an effective way of keeping track of the session but clicking on a regular (<A HREF...>) hypertext link does not result in a form submission, so hidden form fields also cannot support general session tracking.

URL Rewriting:

You can append some extra

the server can associate that session identifier with data it has stored about that session.

For example, with http://tutorialspoint.com/file.htm;sessionid=12345, the session identifier is attached as sessionid=12345 which can be accessed at the web server to identify the client.

URL rewriting is a better way to maintain sessions and works for the browsers when they don't support cookies but here drawback is that you would have generate every URL dynamically to assign a session ID though page is simple static HTML page.

Session Tracking Example :

Index.html

<html> <body> <form action="welcome.jsp"> <input type="text" name="uname"> <input type="submit" value="go"><br/> </form> </body> </html>

Unit 4 – Java


webserver can assign a unique session ID as a cookie to each web client and for subsequent requests from the client they can be recognized using the received cookie.

This may not be an effective way because many time browser does not support a cookie, would not recommend to use this procedure to maintain the sessions.

A web server can send a hidden HTML form field along with a unique session ID as

"hidden" name="sessionid" value="12345">

that, when the form is submitted, the specified name and value are automatically included in the GET or POST data. Each time when web browser sends request back, then session_id value can be used to keep the track of different web

n effective way of keeping track of the session but clicking on a regular (<A HREF...>) hypertext link does not result in a form submission, so hidden form fields also cannot support general session tracking.

You can append some extra data on the end of each URL that identifies the session, and the server can associate that session identifier with data it has stored about that session.

For example, with http://tutorialspoint.com/file.htm;sessionid=12345, the session ed as sessionid=12345 which can be accessed at the web server to


Session Tracking Example :

<form action="welcome.jsp"> <input type="text" name="uname"> <input type="submit" value="go"><br/>

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webserver can assign a unique session ID as a cookie to each web client and for subsequent requests from the client they can be recognized using the received cookie.

This may not be an effective way because many time browser does not support a cookie, would not recommend to use this procedure to maintain the sessions.

A web server can send a hidden HTML form field along with a unique session ID as

that, when the form is submitted, the specified name and value are automatically included in the GET or POST data. Each time when web browser sends request back, then session_id value can be used to keep the track of different web

n effective way of keeping track of the session but clicking on a regular (<A HREF...>) hypertext link does not result in a form submission, so hidden form fields

data on the end of each URL that identifies the session, and the server can associate that session identifier with data it has stored about that session.

For example, with http://tutorialspoint.com/file.htm;sessionid=12345, the session ed as sessionid=12345 which can be accessed at the web server to



Welcome.jsp

<html> <body> <% String name=request.getParameter("uname"); out.print("Welcome "+name); session.setAttribute("user",name); <a href="second.jsp">second jsp page</a> %> </body> </html>

Second.jsp

<html> <body> <% String name=(String)session.getAttribute("user"); out.print("Hello "+name); %> </body> </html>

8 Write a program to

<%@page contentType="text/html"%><%@page pageEncoding="UTF<%@page import="java.sql.*"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <meta http-equiv="Content <title>Example of Java Server Page with JDBC</title> </head> <body> <%

Unit 4 – Java


String name=request.getParameter("uname"); out.print("Welcome "+name);

session.setAttribute("user",name);

<a href="second.jsp">second jsp page</a>

String name=(String)session.getAttribute("user");

Write a program to insert records in a table using JSP.

<%@page contentType="text/html"%> pageEncoding="UTF-8"%>

<%@page import="java.sql.*"%> //W3C//DTD HTML 4.01 Transitional//EN"

"http://www.w3.org/TR/html4/loose.dtd">

equiv="Content-Type" content="text/html; charset=UTF-8"><title>Example of Java Server Page with JDBC</title>

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43

a table using JSP.

8">


String u=request.getParameter("userid");String p=request.getParameter("password");String n=request.getParameter("sname");String e=request.getParameter("eid");String a=request.getParameter("addr");try { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection con=DriverManager.getConnection("jdbc:odbc:sgc","","");/* Passing argument through the question mark */ PreparedStatement ps=con.prepareStateme ps.setString(2,p); ps.setString(3,n); ps.setString(4,a); ps.setString(5,e); int i=ps.executeUpdate(); /*Set the Update query command */ if(i!=0) { response.sendRedirect("index.jsp?msg=Thank You for registering with us in Mrbool !"); } else { response.sendRedirect("registerinsert.jsp?msg=Insertion Failed!! Please try again!!! "); } con.close(); } catch(Exception ex) { out.println(ex); } %> </body> </html>

Unit 4 – Java


String u=request.getParameter("userid"); String p=request.getParameter("password"); String n=request.getParameter("sname"); String e=request.getParameter("eid");

a=request.getParameter("addr");

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection con=DriverManager.getConnection("jdbc:odbc:sgc","","");

/* Passing argument through the question mark */ PreparedStatement ps=con.prepareStatement("insert into login values(?,?,?,?,?)") ;

int i=ps.executeUpdate(); /*Set the Update query command */

response.sendRedirect("index.jsp?msg=Thank You for registering with us in

response.sendRedirect("registerinsert.jsp?msg=Insertion Failed!! Please try

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Connection con=DriverManager.getConnection("jdbc:odbc:sgc","","");

nt("insert into login values(?,?,?,?,?)") ;

response.sendRedirect("index.jsp?msg=Thank You for registering with us in

response.sendRedirect("registerinsert.jsp?msg=Insertion Failed!! Please try


1. Explain JSF Request Processing Life Cycle.

JSF application lifecycle consist of six phases which are as follows

o Restore view phase

o Apply request values phase; process events

o Process validations phase; process events

o Update model values phase; process events

o Invoke application phase; process events

o Render response phase

The six phases show the order in which JSF processes a form. The list shows the phases in their likely order of

Phase 1: Restore view

JSF begins the restore view phase as soon as a link or a button is clicked and JSF receives a request.

During this phase, the JSF builds the view, wires event handlers and validators to components and saves the view in the FacesContext instance. The FacesContext instance will now contains all the information required to process a request.

Unit 5 – Java Server Faces


JSF Request Processing Life Cycle.

JSF application lifecycle consist of six phases which are as follows :

Restore view phase

Apply request values phase; process events

validations phase; process events

Update model values phase; process events

Invoke application phase; process events

Render response phase

The six phases show the order in which JSF processes a form. The list shows the phases execution with event processing at each phase.

JSF begins the restore view phase as soon as a link or a button is clicked and JSF receives

During this phase, the JSF builds the view, wires event handlers and validators to components and saves the view in the FacesContext instance. The FacesContext instance will now contains all the information required to process a request.

Java Server Faces

45

The six phases show the order in which JSF processes a form. The list shows the phases execution with event processing at each phase.

JSF begins the restore view phase as soon as a link or a button is clicked and JSF receives

During this phase, the JSF builds the view, wires event handlers and validators to UI components and saves the view in the FacesContext instance. The FacesContext instance


Phase 2: Apply request values

After the component tree is created/restored, each component in codecode method to extract its new value from the request parameters. Component stores this value. If the conversion fails, an error message is generated and queued on FacesContext. This message will be displayed during the render response with any validation errors.

If any decode methods / event listeners called renderResponse on the current FacesContext instance, the JSF moves to the render response phase.

Phase 3: Process validation

During this phase, the JSF processes all examines the component attribute rules for the validation and compares these rules to the local value stored for the component.

If the local value is invalid, the JSF adds an error message to the FacesContext insand the life cycle advances to the render response phase and display the same page again with the error message.

Phase 4: Update model values

After the JSF checks that the data is valid, it walks over the component tree and set the corresponding server-update the bean properties corresponding to input component's value attribute.

If any updateModels methods called renderResponse on the current FacesContext instance, the JSF moves

Phase 5: Invoke application

During this phase, the JSF handles any applicationform / linking to another page.

Phase 6: Render response

During this phase, the JSF asks container/applicatapplication is using JSP pages. For initial request, the components represented on the page will be added to the component tree as the JSP container executes the page. If this is not an initial request, the component trbe added again. In either case, the components will render themselves as the JSP container/Application server traverses the tags in the page.

After the content of the view is rendered, the response state is savrequests can access it and it is available to the restore view phase.



Phase 2: Apply request values

After the component tree is created/restored, each component in codecode method to extract its new value from the request parameters. Component stores this value. If the conversion fails, an error message is generated and queued on FacesContext. This message will be displayed during the render response with any validation errors.

If any decode methods / event listeners called renderResponse on the current FacesContext instance, the JSF moves to the render response phase.

Phase 3: Process validation

During this phase, the JSF processes all validators registered on component tree. It examines the component attribute rules for the validation and compares these rules to the local value stored for the component.

If the local value is invalid, the JSF adds an error message to the FacesContext insand the life cycle advances to the render response phase and display the same page again with the error message.

Phase 4: Update model values

After the JSF checks that the data is valid, it walks over the component tree and set the -side object properties to the components' local values. The JSF will

update the bean properties corresponding to input component's value attribute.

If any updateModels methods called renderResponse on the current FacesContext instance, the JSF moves to the render response phase.

Phase 5: Invoke application

During this phase, the JSF handles any application-level events, such as submitting a form / linking to another page.

Phase 6: Render response

During this phase, the JSF asks container/application server to render the page if the application is using JSP pages. For initial request, the components represented on the page will be added to the component tree as the JSP container executes the page. If this is not an initial request, the component tree is already built so components need not to be added again. In either case, the components will render themselves as the JSP container/Application server traverses the tags in the page.

After the content of the view is rendered, the response state is saved so that subsequent requests can access it and it is available to the restore view phase.

Java Server Faces

46

After the component tree is created/restored, each component in component tree uses decode method to extract its new value from the request parameters. Component stores this value. If the conversion fails, an error message is generated and queued on FacesContext. This message will be displayed during the render response phase, along

If any decode methods / event listeners called renderResponse on the current

validators registered on component tree. It examines the component attribute rules for the validation and compares these rules to

If the local value is invalid, the JSF adds an error message to the FacesContext instance, and the life cycle advances to the render response phase and display the same page

After the JSF checks that the data is valid, it walks over the component tree and set the side object properties to the components' local values. The JSF will

update the bean properties corresponding to input component's value attribute.

If any updateModels methods called renderResponse on the current FacesContext

level events, such as submitting a

ion server to render the page if the application is using JSP pages. For initial request, the components represented on the page will be added to the component tree as the JSP container executes the page. If this

ee is already built so components need not to be added again. In either case, the components will render themselves as the JSP

ed so that subsequent


2. Explain JSF Expression Language with Example.

JSF provides a rich expression language. We can write normal operations using #{operation-expression} are following.

Provides easy access to elements of a collection which can be a list, map or an array.

Provides easy access to predefined objects such as request. Arithmetic, logical, relational o Automatic type conversion. Shows missing values as empty strings instead of NullPointerException.

Let us understand it with example :

UserData.java

import java.io.Serializableimport java.util.Date; import javax.faces.beanimport javax.faces.bean @ManagedBean(name @SessionScoped public class UserData private static final long private Date createTime private String message public Date getCreateTime return(createTime } public String getMessage return(message); } }

home.xhtml

<?xml version="1.0" encoding<!DOCTYPE html PUBLIC ""http://www.w3.org/TR/xhtml1/DTD/xhtml1<html xmlns="http://www.w3.org/1999/xhtml"



Expression Language with Example.

JSF provides a rich expression language. We can write normal operations using expression} notation. Some of the advantages of JSF Expression languages

Provides easy access to elements of a collection which can be a list, map or an

Provides easy access to predefined objects such as request. Arithmetic, logical, relational operations can be done using expression language.Automatic type conversion. Shows missing values as empty strings instead of NullPointerException.

Let us understand it with example :

Serializable;

bean.ManagedBean; bean.SessionScoped;

name = "userData", eager = true)

implements Serializable {

long serialVersionUID = 1L;

createTime = new Date(); message = "Hello World!";

getCreateTime() { createTime);

getMessage() {

encoding="UTF-8"?> !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> "http://www.w3.org/1999/xhtml"

Java Server Faces

47

JSF provides a rich expression language. We can write normal operations using notation. Some of the advantages of JSF Expression languages

Provides easy access to elements of a collection which can be a list, map or an

perations can be done using expression language.

Shows missing values as empty strings instead of NullPointerException.

//W3C//DTD XHTML 1.0 Transitional//EN"


xmlns:f="http://java.sun.com/jsf/core" xmlns:h="http://java.sun.com/jsf/html" <h:head> <title>JSF Tutorial! </h:head> <h2>Expression Language Example Creation time: <h:outputText value <br/><br/>Message: <h:outputText value </h:body> </html>

3. Explain JSF Structure/Architecture.



"http://java.sun.com/jsf/core" "http://java.sun.com/jsf/html">

JSF Tutorial!</title>

Expression Language Example</h2>

value="#{userData.createTime}"/> Message:

value="#{userData.message}"/>

Structure/Architecture.

Java Server Faces

48


Similar to most of the popular Web Application Frameworks, JSF implements MVC design pattern. The implementation of MVC design pattern helps to design different components separately, and each of logic.

For example, you can crate view component for presentation logic and model component for business logic implementation. A controller is another component, which controls the execution of various model manother in a Web Application.

In JSF, you have a single front controller, which handles all JSF requests mapped to it.

The controller part of the JSF architecture consists of a Controller Servlet, that is, FacesServlet, a centralized configuration file, faceshandlers for the Web Application.

The Model in JSF architecturefrom the model components such as the database these values.

The UI Components are rendered in different ways according to the type of the client. The view delegates this task to separate the renderers , each taking care of one specific output type, such as HTML.

JSF Structure/Architecture is consists of following components:

o The template (most commonly jsp) defines the interface

o The faces-config defines the navigation and the backing beans

o Backing beans handle action processing, navigation processing, and to the logic (business) layer

o Wrapper bean wraps the data POJOs for JSF handling

o Logic layer beans can be injected as defined in the faces

o Model is basic data POJO

JSP Template

<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f"%>

<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h"%>

<f:view>

<html><head><title>Items</title></head><body>

<h:form id="items">

<h:dataTable id="itemlist” value="#{JsfBean.allItems}” var="entry">

<h:column>



Similar to most of the popular Web Application Frameworks, JSF implements MVC design pattern. The implementation of MVC design pattern helps to design different components separately, and each of these components implements different types of

, you can crate view component for presentation logic and model component for business logic implementation. A controller is another component, which controls the execution of various model methods and navigates from one view to another in a Web Application. In JSF, you have a single front controller, which handles all JSF requests mapped to it.

The controller part of the JSF architecture consists of a Controller Servlet, that is, FacesServlet, a centralized configuration file, faces-config.xml, and a set of event handlers for the Web Application.

The Model in JSF architecture is a set of server-side JavaBeans that retrieves the values from the model components such as the database and defines methods on the basis of

The UI Components are rendered in different ways according to the type of the client. The view delegates this task to separate the renderers , each taking care of one specific output type, such as HTML.

Structure/Architecture is consists of following components:

The template (most commonly jsp) defines the interface

config defines the navigation and the backing beans

Backing beans handle action processing, navigation processing, and to the logic (business) layer

Wrapper bean wraps the data POJOs for JSF handling

Logic layer beans can be injected as defined in the faces-config

Model is basic data POJO (Plain Old Java Object)

uri="http://java.sun.com/jsf/core" prefix="f"%>

<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h"%>

<html><head><title>Items</title></head><body>

<h:dataTable id="itemlist” value="#{JsfBean.allItems}” var="entry">

Java Server Faces

49

Similar to most of the popular Web Application Frameworks, JSF implements MVC design pattern. The implementation of MVC design pattern helps to design different

these components implements different types of

, you can crate view component for presentation logic and model component for business logic implementation. A controller is another component, which

ethods and navigates from one view to

In JSF, you have a single front controller, which handles all JSF requests mapped to it.

The controller part of the JSF architecture consists of a Controller Servlet, that is, config.xml, and a set of event

side JavaBeans that retrieves the values and defines methods on the basis of

The UI Components are rendered in different ways according to the type of the client. The view delegates this task to separate the renderers , each taking care of one specific

config defines the navigation and the backing beans

Backing beans handle action processing, navigation processing, and connections

config


<f:facet name="header">

<h:outputText value=""/>

</f:facet>

<h:selectBooleanCheckbox id="itemSelect" value="#{entry.selected}"

rendered="#{entry.canDelete}"/>

<h:outputText value="" rendered="#{not entry.canDelete}"/>

</h:column>

</h:form>

</body></html>

</f:view>

faces-config.xml

Defines the backing beans

Syntax not like Spring

Name used in EL in template

Scope controlled (request, session, etc.)

Defines navigation rules

Based on views

Where from (view)

Which outcome (id)

Where to go (view)

Can match outcomes using wildcards

JSF backing beans

Typical bean with getters and setters and additional methods to handle actions

Store data needed for processing the user actions using setters

Retrieve data using getters and methods

Process actions

Often includes code to wrap data objects

Connects to the rest of the application

Typically via injection



<f:facet name="header">

<h:outputText value=""/>


rendered="#{entry.canDelete}"/>

<h:outputText value="" rendered="#{not entry.canDelete}"/>

Defines the backing beans

Syntax not like Spring

Name used in EL in template

Scope controlled (request, session, etc.)

Defines navigation rules

Based on views

Where from (view)

Which outcome (id)

Where to go (view)

Can match outcomes using wildcards



Retrieve data using getters and methods

Process actions using methods

Often includes code to wrap data objects

Connects to the rest of the application

Typically via injection

Java Server Faces

50





JSF wrapper bean

Wraps basic data POJO

Required to avoid putting UI information in the data POJO

Often includes basic setters and

Can be methods as well

Also includes a setter and getter for the data POJO

4. JSF Standard Components

Following are important h:inputText : Renders a HTML input of type="text", text box. h:inputSecret : Renders a HTML input of type="password h:inputTextarea : Renders a HTML textarea field. h:inputHidden : Renders a HTML input of type=" h:selectBooleanCheckbox h:selectManyCheckbox h:selectOneRadio : Renders a single HTML radio button. h:selectOneListbox : Renders a HTML single list box. h:selectManyListbox : Renders a HTML multiple list box. h:selectOneMenu : Renders a HTML combo box.

h:outputText : Renders a HTML text.

5. JSF Facelet Tags

JSF provides special tags to create common layout for a web applicationtags. These tags gives flexibility to manage common parts of a multiple pages at one place.

Templates <ui:insert> <ui:define> <ui:include> <ui:define>

Parameters <ui:param>

Custom Remove



Wraps basic data POJO

Required to avoid putting UI information in the data POJO

Often includes basic setters and getters for the UI related properties

Can be methods as well

Also includes a setter and getter for the data POJO

JSF Standard Components

Following are important Basic Tags in JSF 2.0: : Renders a HTML input of type="text", text box.

: Renders a HTML input of type="password", text box. : Renders a HTML textarea field.

: Renders a HTML input of type="hidden". h:selectBooleanCheckbox : Renders a single HTML check box. h:selectManyCheckbox : Renders a group of HTML check boxes.

: Renders a single HTML radio button. : Renders a HTML single list box.

: Renders a HTML multiple list box. : Renders a HTML combo box.

: Renders a HTML text.

JSF provides special tags to create common layout for a web applicationtags. These tags gives flexibility to manage common parts of a multiple pages at one

Java Server Faces

51

JSF provides special tags to create common layout for a web application called facelets tags. These tags gives flexibility to manage common parts of a multiple pages at one


6. JSF Validation Tags

f:validateLength : Validates length of a string f:validateLongRange : f:validateDoubleRange f:validateRegex : Validate JSF component with a given regular expression. Custom Validator : Creating a custom validator

7. JSF Database Access.

We can easily integrate JDBC with JSF for Database Access, let’s understand that with

example.

UserData.java

import java.io.Serializableimport java.sql.Connectionimport java.sql.DriverManagerimport java.sql.PreparedStatementimport java.sql.ResultSetimport java.sql.SQLExceptionimport java.util.ArrayListimport java.util.List; import javax.faces.beanimport javax.faces.beanimport javax.faces.event @ManagedBean(name @SessionScoped public class UserData private static final public List<Author ResultSet rs = null PreparedStatement Connection con = String stm = "Select * from authors" List<Author> records try { pst = con.prepareStatement



Validates length of a string : Validates range of numeric value

f:validateDoubleRange : Validates range of float value date JSF component with a given regular expression.

Creating a custom validator.


Serializable; Connection; DriverManager; PreparedStatement; ResultSet; SQLException; ArrayList;

;

bean.ManagedBean; bean.SessionScoped; event.ComponentSystemEvent;

name = "userData", eager = true)

UserData implements Serializable {

final long serialVersionUID = 1L;

Author> getAuthors(){ null;

PreparedStatement pst = null; = getConnection();

"Select * from authors"; records = new ArrayList<Author>();

prepareStatement(stm);

Java Server Faces

52

date JSF component with a given regular expression.



pst.execute(); rs = pst.getResultSet while(rs.next()){ Author author author.setId( author.setName records.add(author } } catch (SQLException e.printStackTrace } return records; } public Connection Connection con = String url = "jdbc:postgresql://localhost/testdb" String user = "user1" String password try { con = DriverManager System.out.println } catch (SQLException System.out.println } finally{ } return con; } }

Home.xhtml

<?xml version="1.0" encoding<!DOCTYPE html PUBLIC ""http://www.w3.org/TR/xhtml1/DTD/xhtml1<html xmlns="http://www.w3.org/1999/xhtml" xmlns:f="http://java.sun.com/jsf/core" xmlns:h="http://java.sun.com/jsf/html"



getResultSet();

()){ author = new Author();

(rs.getInt(1)); setName(rs.getString(2));

author);

SQLException e) { printStackTrace();

Connection getConnection(){ = null;

"jdbc:postgresql://localhost/testdb"; "user1";

password = "user1";

DriverManager.getConnection(url, user, password); println("Connection completed.");

SQLException ex) { println(ex.getMessage());

encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

"http://www.w3.org/1999/xhtml" "http://java.sun.com/jsf/core" "http://java.sun.com/jsf/html">

Java Server Faces

53

//W3C//DTD XHTML 1.0 Transitional//EN"


<h:head> <title>JSF Tutorial!</title> <h:outputStylesheet library </h:head> <h2>JDBC Integration Example <h:dataTable value="#{userData.authors}" styleClass="authorTable" headerClass="authorTableHeader" rowClasses="authorTableOddRow,authorTableEvenRow" <h:column><f:facet name #{c.id} </h:column> <h:column><f:facet name #{c.name} </h:column> </h:dataTable> </h:body> </html>



</title> library="css" name="styles.css" />

JDBC Integration Example</h2> "#{userData.authors}" var="c"

"authorTableHeader"

"authorTableOddRow,authorTableEvenRow"> name="header">Author ID</f:facet>

name="header">Name</f:facet>

Java Server Faces

54


1. Write a note on Hibernate with its Architecture and Deach part in brief.

In order to persist data to a database, Hibernate create an

class mapped with database table).

This object is called Transient object as they are not yet associated with the session or not yet persisted to a database.

To persist the object to database, the instance of

SessionFactory is a singleton instance which implements Factory design pattern. SessionFactory loads hibernate.cfg.xml file and with the help of ConnectionProvider implements all the configuration settings on a d

Each database connection in Hibernate is created by creating an instance of Session interface.

Session represents a single connection with database.

Session objects are created from

Each transaction represents a single atomultiple transactions.

Here are some of the part of the hibernate architecture

Unit 8


Write a note on Hibernate with its Architecture and D

Fig. 1 : Architecture of Hibernate

In order to persist data to a database, Hibernate create an instance of entity class (Java class mapped with database table).

This object is called Transient object as they are not yet associated with the session or not yet persisted to a database.

To persist the object to database, the instance of SessionFactory interface is created.

is a singleton instance which implements Factory design pattern. SessionFactory loads hibernate.cfg.xml file and with the help of TransactionFactory

implements all the configuration settings on a d

Each database connection in Hibernate is created by creating an instance of Session

Session represents a single connection with database.

Session objects are created from SessionFactory object.

Each transaction represents a single atomic unit of work. One Session can span through multiple transactions. Here are some of the part of the hibernate architecture

8 – Hibernate

55

Write a note on Hibernate with its Architecture and Discuss

instance of entity class (Java

This object is called Transient object as they are not yet associated with the session or

nterface is created.

is a singleton instance which implements Factory design pattern. TransactionFactory and

implements all the configuration settings on a database.

Each database connection in Hibernate is created by creating an instance of Session

mic unit of work. One Session can span through


1. SessionFactory (org.hibernate.SessionFactory)

A thread-safe, immutable cache of compiled mappings for a single database. A factory for org.hibernate.Session instances.

A client of org.hibernate.connection.ConnectionProvider. Optionally maintains a second level cache of data that is reusable between

transactions at a process or cluster level.

2. Session (org.hibernate.Session)

A single-threaded, shortapplication and the persistent store.

Wraps a JDBC java.sql.Connection.

Factory for org.hibernate.Transaction.

Maintains a first level cache of persistent the application’s pecollections; this cache is used when navigating the object graph or looking up objects by identifier.

3. Persistent objects and collections

Short-lived, single threaded objects containing persistent state and business function.

These can be ordinary JavaBeans/POJOs.

They are associated with exactly one org.hibernate.Session.

Once the org.hibernate.Session is closed, they will be detached and free to use in any application layer.

4. Transient and detached objects and collections

Instances of persistent classes that are not currently associated with a org.hibernate.Session.

They may have been instantiated by the application and not yet persisted, or they may have been instantiated by a closed org.hibernate.Session.

5. Transaction (org.hibernate.Transaction)

A single-threaded, shortof work.

It abstracts the application from the underlying JDBC, JTA or CORBA transaction.

6. ConnectionProvider (org.hibernate.connection.ConnectionProvider)

A factory for, and pool of, JDBC connections.

It abstracts the application from underlying javax.sql.DataSource or java.sql.DriverManager.

7. TransactionFactory (org.hibernate.TransactionFactory)

A factory for org.hibernate.Transaction instances. It is not exposed to the application, but it can be extended and/or implemented by the developer.

Unit 8


SessionFactory (org.hibernate.SessionFactory)

safe, immutable cache of compiled mappings for a single database. A factory for org.hibernate.Session instances.

A client of org.hibernate.connection.ConnectionProvider. Optionally maintains a second level cache of data that is reusable between transactions at a process or cluster level.

Session (org.hibernate.Session)

threaded, short-lived object representing a conversation between the application and the persistent store.

Wraps a JDBC java.sql.Connection.

Factory for org.hibernate.Transaction.

Maintains a first level cache of persistent the application’s pecollections; this cache is used when navigating the object graph or looking up objects

Persistent objects and collections

lived, single threaded objects containing persistent state and business

an be ordinary JavaBeans/POJOs.

They are associated with exactly one org.hibernate.Session.

Once the org.hibernate.Session is closed, they will be detached and free to use in any

Transient and detached objects and collections

Instances of persistent classes that are not currently associated with a org.hibernate.Session.

They may have been instantiated by the application and not yet persisted, or they may have been instantiated by a closed org.hibernate.Session.

org.hibernate.Transaction)

threaded, short-lived object used by the application to specify atomic units

It abstracts the application from the underlying JDBC, JTA or CORBA transaction. (org.hibernate.connection.ConnectionProvider)

A factory for, and pool of, JDBC connections.

It abstracts the application from underlying javax.sql.DataSource or java.sql.DriverManager.

TransactionFactory (org.hibernate.TransactionFactory)

org.hibernate.Transaction instances. It is not exposed to the application, but it can be extended and/or implemented by the developer.

8 – Hibernate

56

safe, immutable cache of compiled mappings for a single database. A

Optionally maintains a second level cache of data that is reusable between

lived object representing a conversation between the

Maintains a first level cache of persistent the application’s persistent objects and collections; this cache is used when navigating the object graph or looking up objects

lived, single threaded objects containing persistent state and business

Once the org.hibernate.Session is closed, they will be detached and free to use in any

Instances of persistent classes that are not currently associated with a

They may have been instantiated by the application and not yet persisted, or they

lived object used by the application to specify atomic units

It abstracts the application from the underlying JDBC, JTA or CORBA transaction. (org.hibernate.connection.ConnectionProvider)

It abstracts the application from underlying javax.sql.DataSource or

org.hibernate.Transaction instances. It is not exposed to the application,


2. What is HQL? How does it differ from SQL? Give its advantages.

Hibernate Query Language HQL is an but instead of operating on tables and columns, HQL works with persistent objects and their properties.

The Hibernate Query Language (HQL) is an easylanguage designed as an

HQL queries are case insensitive; however, the names of java classes and properties

are case sensitive.If HQL is used in an application define a query for a database, the Hibernate framework automatically generates the S

HQL can also be used to retrieve objects from database through O/R mapping by

performing the following tasks:o Apply restrictions to properties of objectso Arrange the results returned by a query by using the order by clauseo Paginate the resultso Aggregate the records by using group by and having clauseso Use Joins o Create usero Execute subqueries

Following are some of the reasons why HQL is preferred over SQL:

o Provides full support for relation operationso Returns results as objectso Support polymorphic querieso Easy to learn and useo Supports for advanced featureso Provides database independency

HQL consists of the following elements:

o Clauses From : from object [as object_alias] Select : Where : where condition Order by : order by obj1.property1 [asc|desc] [obj2.property2] Group by : Group by obj1.property1,obj1.property2

o Association and Joins

Inner join Left outer join Right Full join

Unit 8


What is HQL? How does it differ from SQL? Give its advantages.

Hibernate Query Language HQL is an object-oriented query language, similar to SQL, but instead of operating on tables and columns, HQL works with persistent objects and their properties. The Hibernate Query Language (HQL) is an easy-to-learn and powerful query language designed as an object-oriented extension to SQL. HQL queries are case insensitive; however, the names of java classes and properties are case sensitive.If HQL is used in an application define a query for a database, the Hibernate framework automatically generates the SQL query and execute it.

HQL can also be used to retrieve objects from database through O/R mapping by performing the following tasks:

Apply restrictions to properties of objects Arrange the results returned by a query by using the order by clausePaginate the results Aggregate the records by using group by and having clauses

Create user-defined functions Execute subqueries

Following are some of the reasons why HQL is preferred over SQL:Provides full support for relation operations

rns results as objects Support polymorphic queries Easy to learn and use Supports for advanced features Provides database independency

HQL consists of the following elements:

From : from object [as object_alias] Select : select [object.property] Where : where condition Order by : order by obj1.property1 [asc|desc] [obj2.property2]Group by : Group by obj1.property1,obj1.property2

Association and Joins Inner join Left outer join Right outer join Full join

8 – Hibernate

57

What is HQL? How does it differ from SQL? Give its advantages.

oriented query language, similar to SQL, but instead of operating on tables and columns, HQL works with persistent objects

learn and powerful query

HQL queries are case insensitive; however, the names of java classes and properties are case sensitive.If HQL is used in an application define a query for a database, the

QL query and execute it.

HQL can also be used to retrieve objects from database through O/R mapping by

Arrange the results returned by a query by using the order by clause

Aggregate the records by using group by and having clauses

Following are some of the reasons why HQL is preferred over SQL:

Order by : order by obj1.property1 [asc|desc] [obj2.property2] Group by : Group by obj1.property1,obj1.property2


o Aggregate functions

avg(…) sum(…) min(…) max(…) count(…)

o Expressions Mathematical operators : +, Binary comparison operators : =,>=,<=,<>,!= Logical operators : String concatenation : ||

o Subquerieso A query within query is known as subquery and is surrounded by

parentheses.

FROM Clause :

You will use FROM clause if you want to load a complete persistent objects into memory. Following is the simple syntax of using FROM clause: String hql = "FROM Employee"; Query query = session.createQuery(hql); List results = query.list()

SELECT Clause :

The SELECT clause provides more control over the result set than the from clause.you want to obtain few properties of objects instead of the complete object, use the SELECT clause. String hql = "SELECT E.firstName FROM Employee E"; Query query = session.createQuery(hql); List results = query.list();

ORDER BY Clause :

To sort your HQL query's results, you will need to use the ORDER BY clause. String hql = "FROM Employee E WHERE E.id > 10 ORDER BY E.salary DESC";Query query = session.createQuery(hql); List results = query.list();

Unit 8


Aggregate functions avg(…) sum(…) min(…) max(…) count(…)

Expressions Mathematical operators : +,-,*,/ Binary comparison operators : =,>=,<=,<>,!= Logical operators : and,or,not String concatenation : ||

Subqueries A query within query is known as subquery and is surrounded by parentheses.

You will use FROM clause if you want to load a complete persistent objects into memory. Following is the simple syntax of using FROM clause:

String hql = "FROM Employee"; Query query = session.createQuery(hql); List results = query.list()

The SELECT clause provides more control over the result set than the from clause.you want to obtain few properties of objects instead of the complete object, use the

String hql = "SELECT E.firstName FROM Employee E"; ry = session.createQuery(hql);

List results = query.list();

ORDER BY Clause : To sort your HQL query's results, you will need to use the ORDER BY clause.

String hql = "FROM Employee E WHERE E.id > 10 ORDER BY E.salary DESC";Query query = session.createQuery(hql); List results = query.list();

8 – Hibernate

58

A query within query is known as subquery and is surrounded by

You will use FROM clause if you want to load a complete persistent objects into

The SELECT clause provides more control over the result set than the from clause. If you want to obtain few properties of objects instead of the complete object, use the

To sort your HQL query's results, you will need to use the ORDER BY clause.

String hql = "FROM Employee E WHERE E.id > 10 ORDER BY E.salary DESC";


USING NAMED Parameters :

Hibernate supports named parameters in its HQL queries.This makes writing HQL queries that accept input from the user String hql = "FROM Employee E WHERE E.id = :employee_id"; Query query = session.createQuery(hql); query.setParameter("employee_id",10); List results = query.list();

UPDATE Clause :

The UPDATE clause can be used to update one or more properties of an one or more objects. String hql = "UPDATE Employee set salary = :salary WHERE id = :employee_id"; Query query = session.createQuery(hql); query.setParameter("salary", 1000); query.setParameter("employee_id", 10); int result = query.executeUpdate(); System.out.println("Rows affected: " + result);

Pagination Using Query :

Query setFirstResult your result set, starting with row 0. Query setMaxResult maxResults of objects. String hql = "FROM Employee"; Query query = session.createQuery(hql); query.setFirstResult(1); query.setMaxResults(10); List results = query.list();

3. Explain the OR Mapping in H

ORM is technique to map object

In other words, it is used to convert the datatype supported in objectprogramming language to a datatype supported by a database.

ORM is also known as O/RM & O/R mapping.

Unit 8


USING NAMED Parameters : Hibernate supports named parameters in its HQL queries.This makes writing HQL queries that accept input from the user.

String hql = "FROM Employee E WHERE E.id = :employee_id"; Query query = session.createQuery(hql); query.setParameter("employee_id",10); List results = query.list();

The UPDATE clause can be used to update one or more properties of an one or more

String hql = "UPDATE Employee set salary = :salary WHERE id = :employee_id"; Query query = session.createQuery(hql); query.setParameter("salary", 1000); query.setParameter("employee_id", 10); int result = query.executeUpdate(); System.out.println("Rows affected: " + result);

Pagination Using Query : Query setFirstResult - This method takes an integer that represents the first row in

starting with row 0.

Query setMaxResult - This method tells Hibernate to retrieve a fixed number maxResults of objects.

String hql = "FROM Employee"; Query query = session.createQuery(hql); query.setFirstResult(1); query.setMaxResults(10); List results = query.list();

OR Mapping in Hibernate.

ORM is technique to map object-oriented data with relational data.

In other words, it is used to convert the datatype supported in objectprogramming language to a datatype supported by a database. ORM is also known as O/RM & O/R mapping.

8 – Hibernate

59

Hibernate supports named parameters in its HQL queries.This makes writing HQL

Query query = session.createQuery(hql); query.setParameter("employee_id",10);

The UPDATE clause can be used to update one or more properties of an one or more

String hql = "UPDATE Employee set salary = :salary WHERE id = :employee_id";

This method takes an integer that represents the first row in

This method tells Hibernate to retrieve a fixed number

In other words, it is used to convert the datatype supported in object-oriented


Mapping should be in the format that can define the mapping of the

o classes with tableso properties with columnso foreign key with associationso and SQL types with Java types.

Mapping can be done with Oracle, DB2, MySql, Sybase and any other relational

databases.

Mapping will be done in the form of XML Document.

In complex applications, a class can be inherited by other classes, which may lead to the

problem of class mismatching. To overcome such problem, the following approach can be used.

o Table-per-classcompletely from the relational model

o Table-per-subclass(normalized mapping):and enables polymorphism.

o Table-per-concreterelationships.

Multiple objects can be

strategies are as follows,o Many-to-one:

a foreign key association.o One-to-many:

to a foreign key association.o Many-to-many:

transparently mapped to a match table.

The important elements of the Hibernate m

o DOCTYPE: Refers to the Hibernate mapping Document Type Declaration (DTD) that should be declared in every mapping file for syntactic validation of the XML.

o <hibernate-mapping> element: inside <hibernate

o <class> element:

database. o <id> element :

the database table.

o <generator> element:

following are some of the commonly used generators. Increment , Sequence, Assigned, Identity, Hilo, Native

o <property> element: database schema.

Unit 8


Mapping should be in the format that can define the mapping of the classes with tables properties with columns foreign key with associations and SQL types with Java types.


Mapping will be done in the form of XML Document.

x applications, a class can be inherited by other classes, which may lead to the problem of class mismatching. To overcome such problem, the following approach can

class-hierarchy: Removes polymorphism and inheritance relationship tely from the relational model

subclass(normalized mapping): De-Normalizes the relational model and enables polymorphism.

concrete-class: Represents inheritance relationship as foreign key

Multiple objects can be mapped to a single row. Polymorphic associations for the 3 strategies are as follows,

Serves as an association in which an object reference is mapped to a foreign key association.

Serves as an association in which a collection of objects is mapped to a foreign key association.

many: Serves as an association in which a collection of objects is transparently mapped to a match table.

The important elements of the Hibernate mapping file are as follows.Refers to the Hibernate mapping Document Type Declaration (DTD)

that should be declared in every mapping file for syntactic validation of the XML.mapping> element: Refers as the first or root element of

inside <hibernate-mapping> tag any number of class may be present.<class> element: Maps a class object with its corresponding entity in the

<id> element : Serves as a unique identifier used to map primary key column of table.

<generator> element: Helps in generation of the primary key for the new record, following are some of the commonly used generators.

Increment , Sequence, Assigned, Identity, Hilo, Native <property> element: Defines standard Java attributes and thedatabase schema.

8 – Hibernate

60


x applications, a class can be inherited by other classes, which may lead to the problem of class mismatching. To overcome such problem, the following approach can

Removes polymorphism and inheritance relationship

Normalizes the relational model

Represents inheritance relationship as foreign key

mapped to a single row. Polymorphic associations for the 3

Serves as an association in which an object reference is mapped to

Serves as an association in which a collection of objects is mapped

Serves as an association in which a collection of objects is

apping file are as follows. Refers to the Hibernate mapping Document Type Declaration (DTD)

that should be declared in every mapping file for syntactic validation of the XML. Refers as the first or root element of Hibernate,

mapping> tag any number of class may be present. Maps a class object with its corresponding entity in the

Serves as a unique identifier used to map primary key column of

Helps in generation of the primary key for the new record,

Defines standard Java attributes and their mapping into


Example :

Employee.java public class Employee private int employeeId; private String name,email; private Address //setters and getters}

Address.java

public class Address { private int addressId; private String addressLine1,city,state,country; private int pincode; private Employee//setters and getters }

Employee.hbm.xml

<?xml version='1.0' encoding='UTF<!DOCTYPE hibernate- "-//Hibernate/Hibernate "http://hibernate.sourceforge.net/hibernate

<hibernate-mapping> <class name="Employee" <id name="employeeId"> <generator class="increment"></generator>

</id> <property name="name"></property> <property name="email"></property> <many-to-one name="address" </class> </hibernate-mapping>

Unit 8


Employee { employeeId;

name,email; Address address;

getters

addressId;

addressLine1,city,state,country; pincode;

Employee employee;

encoding='UTF-8'?>

-mapping PUBLIC //Hibernate/Hibernate Mapping DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

name="Employee" table="emp211"> name="employeeId">

="increment"></generator>

name="name"></property> name="email"></property>

name="address" unique="true" cascade="all"></many-to

8 – Hibernate

61

3.0.dtd">

to-one>


Address.hbm.xml

<?xml version='1.0' encoding='UTF<!DOCTYPE hibernate- "-//Hibernate/Hibernate "http://hibernate.sourceforge.net/hibernate

<hibernate-mapping> <class name="com.javatpoint.Address" <id name="addressId"> <generator class="increment"></gene </id> <property name="addressLine1"></property> <property name="city"></property> <property name="state"></property> <property name="country"></property> </class> </hibernate-mapping>

Hibernate.cfg.xml <?xml version='1.0' encoding='UTF<!DOCTYPE hibernate-configuration "-//Hibernate/Hibernate "http://hibernate.sourceforge.net/hibernate<hibernate-configuration> <session-factory> <property name="hbm2ddl.auto">update</property> <property name="connection.url">jdbc:oracle:thin:@loca <property name="connection.username">system</property> <property name="connection.password">oracle</property> <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property> <mapping resource="employee.hbm.xml"/> <mapping resource="address.hbm.xml"/> </session-factory> </hibernate-configuration>

Unit 8


encoding='UTF-8'?> -mapping PUBLIC

//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

name="com.javatpoint.Address" table="address211">

="increment"></generator>

name="addressLine1"></property> name="city"></property> name="state"></property> name="country"></property>

encoding='UTF-8'?> configuration PUBLIC

//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

configuration>

name="hbm2ddl.auto">update</property> name="connection.url">jdbc:oracle:thin:@localhost:1521:xe</property>name="connection.username">system</property> name="connection.password">oracle</property> name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>

resource="employee.hbm.xml"/> resource="address.hbm.xml"/>

configuration>

8 – Hibernate

62

3.0.dtd">

3.0.dtd">

lhost:1521:xe</property>

name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>


StoreData.java

import org.hibernate.cfg.*;import org.hibernate.*; public class Store {

public static void Configuration cfg.configure("hibernate.cfg.xml"); SessionFactory Session session=sf.openSession(); Transaction Employee e1= e1.setName("Ravi e1.setEmail("[email protected]"); Address address1= address1.setAddressLine1("G address1.setCity("Ghaziabad"); address1.setState("UP"); address1.setCountry("India"); address1.setPincode(201301); e1.setAddress(address1); address1.setEmployee(e1); session.save(e1); session.save(address1); tx.commit(); session.close();}

}

FetchData.java

public class Fetch { public static void Configuration cfg.configure("hibernate.cfg.xml"); SessionFactory Session session=sf.openSession(); Query query=session.createQuery("from List<Employee>

Unit 8


org.hibernate.cfg.*; org.hibernate.*;

void main(String[] args) { Configuration cfg=new Configuration(); cfg.configure("hibernate.cfg.xml"); SessionFactory sf=cfg.buildSessionFactory();

session=sf.openSession(); tx=session.beginTransaction();

e1=new Employee(); e1.setName("Ravi Malik"); e1.setEmail("[email protected]");

address1=new Address(); address1.setAddressLine1("G-21,Lohia nagar"); address1.setCity("Ghaziabad"); address1.setState("UP"); address1.setCountry("India"); address1.setPincode(201301);

e1.setAddress(address1); address1.setEmployee(e1);

session.save(e1); session.save(address1); tx.commit();

session.close();

void main(String[] args) { Configuration cfg=new Configuration(); cfg.configure("hibernate.cfg.xml"); SessionFactory sf=cfg.buildSessionFactory();

session=sf.openSession(); query=session.createQuery("from Employee e");

List<Employee> list=query.list();

8 – Hibernate

63


Query query=session.createQuery("from List<Employee> Iterator<Employee> while(itr.hasNext()){

Employee System.out.println(emp.getEmployeeId()+".getEmail()); Address System.out.println(address.getAddressLine1()+"+ address.getState()+"

} session.close(); System.out.println("success");}

}

4 Explain Hibernate Annotation.

Hibernate Annotations is the powerful way to provide the metadata for the Object and

Relational Table mapping.

Consider we are going to use following EMPLOYEE table to store our objects:

create table EMPLOYEE ( id INT NOT NULL auto_increment, first_name VARCHAR(20) default NULL, last_name VARCHAR(20) default NULL, salary INT default NULL, PRIMARY KEY (id) );

Following is the mapping of Employee class with annotations to map objects with the

defined EMPLOYEE table:

import javax.persistence.*; @Entity @Table(name = "EMPLOYEE") public class Employee { @Id @GeneratedValue @Column(name = "id") private int id;

Unit 8


query=session.createQuery("from Employee e"); List<Employee> list=query.list(); Iterator<Employee> itr=list.iterator(); while(itr.hasNext()){

Employee emp=itr.next(); System.out.println(emp.getEmployeeId()+" "+emp.getName()+"

.getEmail()); Address address=emp.getAddress(); System.out.println(address.getAddressLine1()+" "+address.getCity()+"

address.getState()+" "+address.getCountry());

session.close(); System.out.println("success");

Annotation.

Hibernate Annotations is the powerful way to provide the metadata for the Object and Relational Table mapping.


create table EMPLOYEE ( id INT NOT NULL auto_increment, first_name VARCHAR(20) default NULL, last_name VARCHAR(20) default NULL,

Following is the mapping of Employee class with annotations to map objects with the EMPLOYEE table:

import javax.persistence.*;

@Table(name = "EMPLOYEE")

8 – Hibernate

64

"+emp.getName()+" "+emp

"+address.getCity()+" "

Hibernate Annotations is the powerful way to provide the metadata for the Object and


Following is the mapping of Employee class with annotations to map objects with the


@Column(name = "first_name") private String firstName; @Column(name = "last_name") private String lastName; @Column(name = "salary") private int salary;

public Employee() {} public int getId() {

return id; }

public void setId( int id ) { this.id = id; }

public String getFirstName() { return firstName; }

public void setFirstName( String first_name ) { this.firstName = first_name; }

public String getLastName() { return lastName; }

public void setLastName( String last_name ) { this.lastName = last_name; }

public int getSalary() { return salary; }

public void setSalary( int salary ) { this.salary = salary; }

}

@Entity Annotation:

Employee class which marks this class as an entity bean

@Table Annotation: The @Table annotation allows you to specify the details of the table that will be

used to persist the entity in the database.

@Id and @GeneratedValue Annotations: Each entity bean will have a primary key, which you annotate on the class with

the @Id annot @GeneratedValue

Unit 8


@Column(name = "first_name")

@Column(name = "last_name")

@Column(name = "salary")

public void setId( int id ) {

public String getFirstName() {

public void setFirstName( String first_name ) { this.firstName = first_name;

public String getLastName() {

public void setLastName( String last_name ) { this.lastName = last_name;

public void setSalary( int salary ) {

Employee class which marks this class as an entity bean

The @Table annotation allows you to specify the details of the table that will be used to persist the entity in the database.

@Id and @GeneratedValue Annotations: Each entity bean will have a primary key, which you annotate on the class with

annotation @GeneratedValue is same as Auto Increment

8 – Hibernate

65

The @Table annotation allows you to specify the details of the table that will be

Each entity bean will have a primary key, which you annotate on the class with


@Column Annotation:

The @Column annotation is used to specify the details of the column to which a field or property will be mapped. You can use column annotation with the following most commonly used

name attribute permits the name of the column to be explicitly specified. length attribute permits the size of the column used to map a value particularly

for a String value. nullable attribute permits the column to be marked NOT NULL when the

is generated. unique attribute permits the column to be marked as containing only unique

values.

Unit 8


@Column Annotation: The @Column annotation is used to specify the details of the column to which a field or property will be mapped. You can use column annotation with the following most commonly used attributes:

attribute permits the name of the column to be explicitly specified.attribute permits the size of the column used to map a value particularly

for a String value. attribute permits the column to be marked NOT NULL when the

attribute permits the column to be marked as containing only unique

8 – Hibernate

66

The @Column annotation is used to specify the details of the column to which a field or property will be mapped. You can use column annotation with the

attribute permits the name of the column to be explicitly specified. attribute permits the size of the column used to map a value particularly

attribute permits the column to be marked NOT NULL when the schema

attribute permits the column to be marked as containing only unique


1. Explain Spring MVC

Spring’s web MVC framework is, like many other web MVC frameworks, requestdesigned around a central other functionality that facilitates the development of web applications.

Spring’s DispatcherServlet is completely integrated with Spring IoC container and allows us to use every other feature of S

Following is the Request process lifecycle of Spring 3.0 MVC:

1. The client sends a request to web container in the form of http request.2. This incoming request is intercepted by Front controller (DispatcherServlet) and it

will then tries to find out 3. With the help of Handler Mappings, the DispatcherServlet will dispatch the request

to appropriate Controller.4. The Controller tries to process the request and returns the Model and View object in

form of ModelAndView instance t5. The Front Controller then tries to resolve the View (which can be JSP, Freemarker,

Velocity etc) by consulting the View Resolver object.6. The selected view is then rendered back to client.

Unit 7 –


MVC Architecture

Fig. 1 : Spring MVC Architecture

Spring’s web MVC framework is, like many other web MVC frameworks, requestdesigned around a central servlet that dispatches requests to controllers and offers other functionality that facilitates the development of web applications.

Spring’s DispatcherServlet is completely integrated with Spring IoC container and allows us to use every other feature of Spring. Following is the Request process lifecycle of Spring 3.0 MVC:

The client sends a request to web container in the form of http request.This incoming request is intercepted by Front controller (DispatcherServlet) and it will then tries to find out appropriate Handler Mappings. With the help of Handler Mappings, the DispatcherServlet will dispatch the request to appropriate Controller. The Controller tries to process the request and returns the Model and View object in form of ModelAndView instance to the Front Controller. The Front Controller then tries to resolve the View (which can be JSP, Freemarker, Velocity etc) by consulting the View Resolver object. The selected view is then rendered back to client.

– Spring MVC

67

Spring’s web MVC framework is, like many other web MVC frameworks, request-driven, servlet that dispatches requests to controllers and offers

other functionality that facilitates the development of web applications. Spring’s DispatcherServlet is completely integrated with Spring IoC container and allows

The client sends a request to web container in the form of http request. This incoming request is intercepted by Front controller (DispatcherServlet) and it

With the help of Handler Mappings, the DispatcherServlet will dispatch the request

The Controller tries to process the request and returns the Model and View object in

The Front Controller then tries to resolve the View (which can be JSP, Freemarker,


Features of Spring 3.0 : Spring 3.0 framework supports Java 5. It provides annotation based configuration

support. Java 5 features such as generics, annotations, varargs etc can be used in Spring.

A new expression language Spring Expression Language SpEL is being introduced. The Spring Expression Language can be used while defining the XML and Annotation based bean definition.

Spring 3.0 framework supports REST web services.

Data formatting can never be so easy. Spring 3.0 supports annotation based formatting. We can now use the @DateFimeForm@NumberFormat(style=Style.CURRENCY) annotations to convert the date and currency formats.

Spring 3.0 has started support to JPA 2.0.

Configuring Spring 3.0 MVC : The entry point of Spring 3.0 MVC is the DispatcherServlet.

servlet class which implements HttpServlet base class. Thus we need to configure it in web.xml.

<web-app> <servlet> <servlet-name>example <servlet-class>org.springframework.web.servlet.DispatcherServlet <load-on-startup> </servlet> <servlet-mapping> <servlet-name>example <url-pattern>*.html </servlet-mapping></web-app>

In above code snippet, we have configure DispatcherServlet in web.xml. Note that we

have mapped *.html url pattern with example DispatcherServlet. Thus any url with *.html pattern will call Spring MVC Front controller.

Once the DispatcherServlet is initialized, it will looks for a file names [servlet

servlet.xml in WEB-INF folder of web application. In above example, the framework will look for file called example

Unit 7 –


framework supports Java 5. It provides annotation based configuration

support. Java 5 features such as generics, annotations, varargs etc can be used in Spring.

A new expression language Spring Expression Language SpEL is being introduced. The ssion Language can be used while defining the XML and Annotation based

Spring 3.0 framework supports REST web services.

Data formatting can never be so easy. Spring 3.0 supports annotation based formatting. We can now use the @DateFimeFormat(iso=ISO.DATE) and @NumberFormat(style=Style.CURRENCY) annotations to convert the date and currency

Spring 3.0 has started support to JPA 2.0.

Configuring Spring 3.0 MVC : The entry point of Spring 3.0 MVC is the DispatcherServlet. DispatcherServlet is a normal servlet class which implements HttpServlet base class. Thus we need to configure it in

example</servlet-name> org.springframework.web.servlet.DispatcherServlet

startup>1</load-on-startup>

example</servlet-name>

*.html</url-pattern> ng>

In above code snippet, we have configure DispatcherServlet in web.xml. Note that we have mapped *.html url pattern with example DispatcherServlet. Thus any url with *.html pattern will call Spring MVC Front controller.

DispatcherServlet is initialized, it will looks for a file names [servletINF folder of web application. In above example, the framework will

look for file called example-servlet.xml.

– Spring MVC

68

framework supports Java 5. It provides annotation based configuration support. Java 5 features such as generics, annotations, varargs etc can be used in Spring.

A new expression language Spring Expression Language SpEL is being introduced. The ssion Language can be used while defining the XML and Annotation based

Data formatting can never be so easy. Spring 3.0 supports annotation based formatting. at(iso=ISO.DATE) and

@NumberFormat(style=Style.CURRENCY) annotations to convert the date and currency

DispatcherServlet is a normal servlet class which implements HttpServlet base class. Thus we need to configure it in

org.springframework.web.servlet.DispatcherServlet</servlet-class>

In above code snippet, we have configure DispatcherServlet in web.xml. Note that we have mapped *.html url pattern with example DispatcherServlet. Thus any url with

DispatcherServlet is initialized, it will looks for a file names [servlet-name]-INF folder of web application. In above example, the framework will


2. Explain Bean Life Cycle.

The life cycle of a Spring bean is easy to understand. When a bean is instantiated, it may be required to perform some initialization to get it into a usable state. Similarly, when the bean is no longer required and is removed from the container, some cleanup may brequired.

Though, there is lists of the activities that take place behind the scenes between the time of bean Instantiation and its destruction, but this chapter will discuss only two important bean lifecycle callback methods which are required at the tiinitialization and its destruction.

To define setup and teardown for a bean, we simply declare the <bean> with initmethod and/or destroymethod that is to be called on the bean immediateldestroy-method specifies a method that is called just before a bean is removed from the container.

Here is the content of

public class HelloWorld { private String message; public void setMessage( this.message = message } public void getMessage(){ System.out.println("Your Message : " } public void init(){ System.out.println("Bean is going through init." } public void destroy(){ System.out.println("Bean will destroy now." } }

Following is the content of the

hook registerShutdownHook()AbstractApplicationContext class. This will ensures a graceful shutdown and calls the relevant destroy methods.

Unit 7 –


Explain Bean Life Cycle.

cycle of a Spring bean is easy to understand. When a bean is instantiated, it may be required to perform some initialization to get it into a usable state. Similarly, when the bean is no longer required and is removed from the container, some cleanup may b

Though, there is lists of the activities that take place behind the scenes between the time of bean Instantiation and its destruction, but this chapter will discuss only two important bean lifecycle callback methods which are required at the tiinitialization and its destruction.

To define setup and teardown for a bean, we simply declare the <bean> with initmethod and/or destroy-method parameters. The init-method attribute specifies a method that is to be called on the bean immediately upon instantiation. Similarly,

method specifies a method that is called just before a bean is removed from the

Here is the content of HelloWorld.java file:

(String message){ message;

(){ "Your Message : " + message);

"Bean is going through init.");

"Bean will destroy now.");

Following is the content of the MainApp.java file. Here you need to register a shutdown registerShutdownHook() method that is declared on the

AbstractApplicationContext class. This will ensures a graceful shutdown and calls the relevant destroy methods.

– Spring MVC

69

cycle of a Spring bean is easy to understand. When a bean is instantiated, it may be required to perform some initialization to get it into a usable state. Similarly, when the bean is no longer required and is removed from the container, some cleanup may be

Though, there is lists of the activities that take place behind the scenes between the time of bean Instantiation and its destruction, but this chapter will discuss only two important bean lifecycle callback methods which are required at the time of bean

To define setup and teardown for a bean, we simply declare the <bean> with init-method attribute specifies a

y upon instantiation. Similarly, method specifies a method that is called just before a bean is removed from the

file. Here you need to register a shutdown method that is declared on the

AbstractApplicationContext class. This will ensures a graceful shutdown and calls the


import org.springframeworkimport org.springframework public class MainApp { public static void main AbstractApplicationContextClassPathXmlApplicationContext HelloWorld obj = (HelloWorld obj.getMessage(); context.registerShutdownHook } }

Following is the configuration file Beans.xml required for init and destroy methods:

<?xml version="1.0" encoding <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema xsi:schemaLocation= http://www.springframework.org/schema/beans/spring

<bean id="helloWorld" class="com.HelloWorld" init-method="init" <property name </bean>

</beans>

3. Explain Transaction Management in Spring MVC.

A database transaction is a sequence of actions that are treated as a single unit of work. These actions should either complete entirely or take no effect at all. Transaction management is an important part of and RDBMS oriented enterprise applications to ensure data integrity and consistency. The concept of transactions can be described with following four key properties described as

o Atomicity: A transaction should be treated as a single unit of operation which

means either the entire sequence of oo Consistency: This represents the consistency of the referential integrity of the

database, unique primary keys in tables etc.

Unit 7 –


springframework.context.support.AbstractApplicationContextspringframework.context.support.ClassPathXmlApplicationContext

{ main(String[] args) {

AbstractApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");

HelloWorld) context.getBean("helloWorld");

registerShutdownHook();


encoding="UTF-8"?>

"http://www.springframework.org/schema/beans" "http://www.w3.org/2001/XMLSchema-instance"

="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-3.0.xsd"

helloWorld" "com.HelloWorld"

"init" destroy-method="destroy"> name="message" value="Hello World!"/>

Explain Transaction Management in Spring MVC.

A database transaction is a sequence of actions that are treated as a single unit of work. These actions should either complete entirely or take no effect at all. Transaction management is an important part of and RDBMS oriented enterprise applications to ensure data integrity and consistency. The concept of transactions can be described with following four key properties described as ACID:

A transaction should be treated as a single unit of operation which means either the entire sequence of operations is successful or unsuccessful.

This represents the consistency of the referential integrity of the database, unique primary keys in tables etc.

– Spring MVC

70

AbstractApplicationContext; ClassPathXmlApplicationContext;


"http://www.springframework.org/schema/beans 3.0.xsd">

A database transaction is a sequence of actions that are treated as a single unit of work. These actions should either complete entirely or take no effect at all. Transaction management is an important part of and RDBMS oriented enterprise applications to ensure data integrity and consistency. The concept of transactions can be described with

A transaction should be treated as a single unit of operation which perations is successful or unsuccessful.

This represents the consistency of the referential integrity of the


o Isolation: There may be many transactions processing with the same data set at the same time, each transaction should be isolated from others to prevent data corruption.

o Durability: Once a transaction has completed, the results of this transaction have to be made permanent and cannot be erased from the database due to system failure.

Spring supports two types of transaction management:

o Programmatic transaction management:transaction with the help of programming. That gives you eit is difficult to maintain.

o Declarative transaction management:management from the business code. You only use annotations or XML based configuration to manage the transactions.

Declarative transaction management is preferable over programmatic transaction

management though it iswhich allows you to control transactions through your code.

Spring Transaction Abstractions The key to the Spring transaction abstraction is defined by the

org.springframework.transaction.PlatformTransactionManager interface, which is as follows:

public interface PlatformTransactionManager

TransactionStatus getTransaction throws TransactionExceptionvoid commit(TransactionStatusvoid rollback(TransactionStatus

}

Sr. No. Method & Description

1 TransactionStatus getTransaction(TransactionDefinition definition)

This method returns a currently active transaction or create a new one, according to the specified propagation behavior.

2 void commit(TransactionStatus status)

This method commits the given transaction, with regard to its status.

3 void rollback(TransactionStatus s

This method performs a rollback of the given transaction.

Unit 7 –


There may be many transactions processing with the same data set at ime, each transaction should be isolated from others to prevent data

Once a transaction has completed, the results of this transaction have to be made permanent and cannot be erased from the database due to system

supports two types of transaction management: Programmatic transaction management: This means that you have manage the transaction with the help of programming. That gives you extreme flexibility, but it is difficult to maintain. Declarative transaction management: This means you separate transaction management from the business code. You only use annotations or XML based configuration to manage the transactions.

Declarative transaction management is preferable over programmatic transaction management though it is less flexible than programmatic transaction management, which allows you to control transactions through your code.

Spring Transaction Abstractions The key to the Spring transaction abstraction is defined by the org.springframework.transaction.PlatformTransactionManager interface, which is as

PlatformTransactionManager { getTransaction(TransactionDefinition definition);

TransactionException; TransactionStatus status) throws TransactionException;TransactionStatus status) throws TransactionException;

Method & Description TransactionStatus getTransaction(TransactionDefinition definition)

returns a currently active transaction or create a new one, according to the specified propagation behavior. void commit(TransactionStatus status)

This method commits the given transaction, with regard to its status.void rollback(TransactionStatus status)

This method performs a rollback of the given transaction.

– Spring MVC

71

There may be many transactions processing with the same data set at ime, each transaction should be isolated from others to prevent data

Once a transaction has completed, the results of this transaction have to be made permanent and cannot be erased from the database due to system

This means that you have manage the xtreme flexibility, but

This means you separate transaction management from the business code. You only use annotations or XML based

Declarative transaction management is preferable over programmatic transaction less flexible than programmatic transaction management,

The key to the Spring transaction abstraction is defined by the org.springframework.transaction.PlatformTransactionManager interface, which is as

; ;

TransactionStatus getTransaction(TransactionDefinition definition)

returns a currently active transaction or create a new one,

This method commits the given transaction, with regard to its status.

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