pengenalan java.pdf

8/9/2019 Pengenalan JAVA.pdf

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A RM I N L A W I

P R O G R A M P A S C A S A R A J A N U N H A S

Pemrograman Jaringan:

Pengenalan Java


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Pengenalan java

Menerapkan compiler dan interpreter

public class myCetak {public static void main(String args[])

{System.out.println(“Hello World!”);

}

}

compiler

-----------------------------------------------------------------------------------------------------------------

--------------------------------------------

interpreter

program.java program.class javac program.java

java program11010101

2

bytecode


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Karakteristik Multi-platform

public class myCetak {public static void main(String args[])

{System.out.println(“Hello World!”);

}}

compiler

program.java program.class

Windows Linux Solaris MacOS

JVM

-------------------------------------------------------------------------------------------------------------------------------------------------------------

interpreterinterpreterinterpreter

3

interpreter


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Software yang dibutuhkan

Java Standrd Edition (SE) Development Kit (JDK)

Dapat didownload gratis dihttp://developers.sun.com/downloads/

JDK yang digunakan pada MK ini adalah versi terbarusaat ini: JDK1.6.0 update 10

Text Editor: Notepad, Edit, dll

4

Java IDE:Jcreator, Eclipse, NetBeans, dll


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OOP dan Java

Java adalah bahasa pemrograman murni berbasisobject-oriented (OO)

OOP: Program bekerja atas interaksi ataukomunikasi antar obyek (object interprocess)

OO-program dapat dipandang sebagai sistemtersebar (distributed system)

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Apa itu obyek?

Segala sesuatu dapat dipandang sbg obyek

Karateristik obyek Memiliki atribut sebagai status (state/variable)

Memiliki tingkah laku (behavior) atau method

variabel/

statemethod/

behavior

Object model

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Bagaimana membuat obyek

Obyek dikonstruksi/dirancang dari prototipe ataublueprint yang telah ditetapkan (class)

Contoh:

resep classkue obyek

Bahan:

1 kg gula2 sdk mentegadan sterusnya.

Cara Membuat:Campursemua lalupanaskan dan seterusnya

Resep Kue 1

Kue 2

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Contoh oop dalam java

class mhs {private String nama;private String nim;private String ttl;private String agama;

public mhs(String nama, String nim, String m, String agama) {this.nama = nama;

this.nim = nim;this.ttl = ttl;this.agama = agama;

}

public String getNama() {return this.nama;

}

public String getNim() {return nim;

}

public static void main(String args[]) {mhs m = new mhs(“Armin”, “132133693”, “19”, “Islam”);System.out.println(“Nama =“ + m.getNama());

}

}

variabel/state

konstruktor

method/

behavior

obyek m

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Ciri-ciri oop

Abstraksi (abstraction)

Pengabstrakan atau penyembunyian kerumitan dari suatu proses

Pembungkusan (encapsulation)

Abstraksi dilakukan dengan cara pembungkusan (kapsulasi) semua

kode dan data kedalam satu entitas tunggal (obyek)

Pewarisan (inheritance)

Implementasi khusus dalam OOP yang dapat menurunkan prilaku kesub-class atau menerima prilaku dari super-class

Kebanyak-rupaan ( polymorphism)Kemampuan obyek mengungkap banyak hal melalui suatu cara yangsama. Obyek dapat menjalankan prilaku-prilaku atau metode-metode yang diturunkan dari beberapa superclassnya

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Netprog 2000 - Java NetworkPro rammin

10

Important Java Packages

java.net TCP/IP networking

java.io I/O streams & utilities

java.rmi Remote Method Invocation

java.securitySecurity policies

java.lang Threading classes


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IP Addresses & Hostnames

java.net.InetAddress class

Represents a single IP address

Factory class – no public constructor

Performs transparent DNS lookups or reverselookups

java.net.UnkownHostException thrown if

DNS system can’t find IP address for specific host

http://java.sun.com/products/jdk/1.3/docs/api/java/net/InetAddress.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/UnknownHostException.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/UnknownHostException.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/InetAddress.html


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TCP Server Sockets

java.net.ServerSocket class

Binds to a local port to listen for initial connections

Can be bound to a local IP for multi-homed

machines accept() method returns a java.net.Socket,

not an integer descriptor

http://java.sun.com/products/jdk/1.3/docs/api/java/net/ServerSocket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/Socket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/Socket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/ServerSocket.html


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TCP Client Sockets

java.net.Socket class

Combines socket with socket options (timeout,linger, keep alive, no delay, etc)

Encapsulates a java.io.InputStream and ajava.io.OutputStream – can be retrieved for

use in a layered I/O system

http://java.sun.com/products/jdk/1.3/docs/api/java/net/Socket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/io/InputStream.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/io/OutputStream.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/io/OutputStream.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/io/InputStream.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/Socket.html


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UDP Sockets

java.net.DatagramSocket class

Java makes no distinction between client/server forUDP sockets

Connected mode UDP supported in Java 2

Can be bound to both a local port & a local IPaddress – multi-homed support

Supports some socket options (timeout, buffer size)

http://java.sun.com/products/jdk/1.3/docs/api/java/net/DatagramSocket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/DatagramSocket.html


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UDP Datagrams

java.net.DatagramPacket class

Expects a byte array of data

Address optional for connected-mode UDP

This class is final – can’t be extended! java.net.DatagramSocket instances can only

send instances of java.net.DatagramPacket

http://java.sun.com/products/jdk/1.3/docs/api/java/net/DatagramPacket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/DatagramSocket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/DatagramPacket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/DatagramPacket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/DatagramSocket.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/net/DatagramPacket.html


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Threading

Java doesn’t support the notion of forkingprocesses; how do we support concurrency?

–Java was designed to support multi-threading!

– In server environments we can spawn new

threads to handle each client

– Thread groups allow for collective control

of many threads

http://java.sun.com/products/jdk/1.3/docs/api/java/lang/Thread.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/lang/ThreadGroup.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/lang/ThreadGroup.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/lang/Thread.html


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Java Servlets

Servlets are the Java analog to CGI

Advantages of servlets: full access to other Java APIs,persistence between invocations, guaranteed

portability Servlets can be generic services or specific to HTTP


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HTTP Servlets

javax.servlet.http.HttpServlet class

Uses HTTP to receive requests and generateresponses

Full support for all HTTP methods, cookies, sessions,persistent connections

Servlets can be chained – example: de-blink servlet

http://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/HttpServlet.htmlhttp://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/HttpServletRequest.htmlhttp://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/HttpServletResponse.htmlhttp://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/Cookie.htmlhttp://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/Cookie.htmlhttp://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/HttpServletResponse.htmlhttp://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/HttpServletRequest.htmlhttp://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/HttpServlet.html


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Java Applets

Client-side Java programs that run in a browser

Applets have special security restrictions called theapplet sandbox

Only applets loaded over the network are subject tothe applet sandbox

The applet sandbox is controlled by ajava.lang.SecurityManager

http://java.sun.com/products/jdk/1.3/docs/api/java/lang/SecurityManager.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/lang/SecurityManager.html


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Applet Sandbox

Can’t load libraries or define native methods

Can’t access local host filesystem

Can’t open sockets to hosts other than

originating host

Can’t use Runtime.exec()

Applet windows have a unique appearance

Restricted access to certain system properties

http://java.sun.com/products/jdk/1.3/docs/api/java/lang/Runtime.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/lang/Runtime.html


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Escaping the Applet Sandbox

Browsers can define their own security policy via anew security manager

Applets can be signed and executed as trusted

content Security policies may vary from browser to browser,

even for signed applets

http://java.sun.com/products/jdk/1.3/docs/api/java/lang/SecurityManager.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/lang/SecurityManager.html


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Remote Method Invocation (RMI)

RMI is the Java analog to RPC RMI servers use a naming service (rmiregistry) to

register remote objects

RMI servers use a special security policyimplemented by RMISecurityManager

The default RMI transport mechanism is via TCPsockets – this is transparent to RMI code!

Any object transferred in an RMI call mustimplement the Serializable interface

http://java.sun.com/products/jdk/1.3/docs/api/java/rmi/server/UnicastRemoteObject.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/rmi/RMISecurityManager.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/io/Serializable.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/io/Serializable.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/rmi/RMISecurityManager.htmlhttp://java.sun.com/products/jdk/1.3/docs/api/java/rmi/server/UnicastRemoteObject.html


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Netprog 2000 - Java Network24

Java Naming & Directory Interface (JNDI)

JNDI provides a generic API that can be used tointerface with any naming system

JNDI uses SPIs (service provider interfaces) to

access many different types of naming & directoryservices from the JNDI API

Sun supplies JNDI SPIs for LDAP, NIS, COS(CORBA naming), RMI registry & local filesystem
http://java.sun.com/products/jndi/index.htmlhttp://java.sun.com/products/jndi/index.html

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