network socket programming with java

Q7M1 – SC Dudy Fathan Ali S.Kom

Network Socket ProgrammingQ7M1

Dudy Fathan Ali, S.Kom (DFA)2017

CEP - CCITFakultas Teknik Universitas Indonesia

Consider this scenario..


Hello, I want a pizza.

Guys, bob wants a pizza!

Bob

Pizza Store

Consider this scenario..


Pizza Store

Standard Operational Procedure

Hmm..


Client/Server Architecture


Bob

[Client]Pizza Store

[Server]

The client places a request or orderto the server.

The server processes the request of the client

The communicationbetween the client and the server is usually through a network.

The Client/Server model is an application development architecture designed to separate the presentation of data from its internal processing and storage.



Pizza Store

The processing that is done by the server is hidden from the client.



Steve

Bob

John

One server can service multiple clients.



The server and the client are not necessarily hardware components. They can be programs working on the same machine or on different machines.

Internet Protocol


The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.

-- Source: wikipedia.org

-- Source: google.com

Internet Protocol


implicit rules in conversation?

Internet Protocol


o Data is sent from one machine to another in form of packets. o Rules govern packaging of data into packets, speed of transmission, and

reassembling of data into its original form.o These rules are called network protocols.

Communication rules between computers

IP Address & Port


IP Address & Port


The TCP protocol requires two data items: the IP address and the port number.

172.17.8.192 : 80IP Address Port

o Well-known portso Registered portso Dynamic/Private ports

IP Address & Port


IP Addresses of Popular Websites

Sockets


Sockets are used to handle the communication links between applications over the network. Further communication between the client and the server is through the socket.

-- Source: NIIT Courseware Q7M1

Java Classes for Network Programming


o The java.net package of the Java programming language contains classes and interfaces that provide support for networking.

o Networking classes contain methods to perform tasks, such as opening and closing a connection to remote machine, sending and receiving data packets and accessing resources on the Web.



Classes of the java.net Package:o DatagramPacket

o Represents a datagram packet. o DatagramSocket

o Represents a datagram socket object that can send and receive datagram packets.

o MulticastSocketo Creates a multicast datagram socket object that is used to send and receive

datagram packets to groups.o InetAddress

o Represents an IP address.o ServerSocket

o Represents a TCP/IP server socket object that receives connection requests from the clients.



The InetAddress Class:o Represents an IP address.o Contains the following static methods to initialize InetAddress

objects:o public static InetAddress getLocalHost()o public static InetAddress getByName(String host)o public static InetAddress[] getAllByName(String host)



The non-static methods of the InetAddress class are:o public boolean equals(Object obj)o public byte[] getAddress()o public String getHostAddress()o public String toString()



Code Example:

Result:

Returns an InetAddress object that contains the IP address of the local computer.

Returns the IP address of the InetAddressobject as a String.

TCP vs UDP


Creating Application Using UDP


o UDP is a fast, connectionless, and unreliable protocol.o UDP sockets use UDP protocol for communication over a network.o The java.net package provides the following two classes that

enable you to implement UDP sockets in a Java application:o DatagramPacket classo DatagramSocket class

o The DatagramPacket object is a data container that consists of datagram packets that are sent or received over the network.

o The constructor used to initialize DatagramPacket objects are:o public DatagramPacket( byte[] buffer, int

buffer_length)o public DatagramPacket( byte[] buffer, int

buffer_length, InetAddress address, int port)



o DatagramSocket class encapsulates the functionality to handle DatagramPacket objects.

o The constructors used to initialize DatagramSocket object are:o public DatagramSocket()o public DatagramSocket(int port)o public DatagramSocket(int port, InetAddress address)



Code Example [DataSender]:



Code Example [DataReceiver]:

Demonstration-Implementing UDP


Create a Client/Server application where the server can broadcast messages to all the clients of 233.0.0.1 group.


Thank You!Dudy Fathan Ali, S.Kom

[email protected]

mailto:[email protected]

network socket programming with java

Technology