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CREATING AND USINGJAVA SOCKETS:

By P.Vinitha

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Sockets and Ports

In order tocommunicate with a remote host the

Java client must first create a Socket, which will

establish the TCP connection. Whileestablishing theconnection a host name

and port numbermust be specified.

Theremust be a server actively listening on the

specified port or theconnection will fail with

IOException.

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Sockets

The java.net.Socket class allows us to

perform all four fundamental socket

operationsconnecting toremotemachines

sending data

receiving dataclosing theconnection.

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Constructors of java.net.Socket class

Public Socket() throws IOException

Creates an unbound server socket.

When using this constructor, use theconnect() method when you are ready

to bind the server socket

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Methods of Socket Class

public void connect(SocketAddress host,

int timeout) throws IOException

This method connects the socket to thespecified host. This method is needed only

when you instantiated the Socket using the

no-argument constructor.

public InetAddress getInetAddress()

This method returns the address of the other

computer that this socket is connected to.

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Methods of Socket Class

public int getPort()

Returns the port the socket is bound toon the

remotemachine. public int getLocalPort()

Returns the port the socket is bound toon the

localmachine.

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Methods of Socket Class

public SocketAddress

getRemoteSocketAddress()

Returns the address of theremote socket. public InputStream getInputStream() throws

IOException

Returns the input streamof the socket. The inputstream is connected to theoutput streamof the

remote socket.

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Methods of Socket Class

public OutputStream getOutputStream()

throws IOException

Returns theoutput streamof the socket. Theoutput stream is connected to the input

streamof theremote socket

public void close() throws IOExceptionCloses the socket, which makes this Socket

object nolongercapableof connecting

again to any server.

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Program to read a webpage from a

website

import java.net.*;

import java.io.*;

class readurl {

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

BufferedReader br1=new BufferedReader(new

InputStreamReader(System.in));String filename;

System.out.print("Enter the webpage address:");filename=br1.readLine();

URL myurl=new URL(filename);

InputStream in=myurl.openStream();

BufferedReader br=new BufferedReader(newInputStreamReader(in));

String str;while((str=br.readLine())!=null)

System.out.println(str);

br.close();

}}