Problem 3 Java Programming

Reimplement the echo server and client using TCP. The TCP server should support multiple client connections. Each connection should be handled by a thread. After sending a response (echo), the thread execution should stop. The main server thread, as previously, is supposed to run in a loop until manual termination.

This is the given UDP Client/ Server programme

/*

UDPEchoClient.java

A simple echo client with no error handling

*/

package dv201.labb2;

import java.io.IOException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetSocketAddress;

import java.net.SocketAddress;

public class UDPEchoClient {

public static final int BUFSIZE= 1024;

public static final int MYPORT= 0;

public static final String MSG= "An Echo Message!";

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

byte[] buf= new byte[BUFSIZE];

if (args.length != 2) {

System.err.printf("usage: %s server_name port ", args[1]);

System.exit(1);

}

/* Create socket */

DatagramSocket socket= new DatagramSocket(null);

/* Create local endpoint using bind() */

SocketAddress localBindPoint= new InetSocketAddress(MYPORT);

socket.bind(localBindPoint);

/* Create remote endpoint */

SocketAddress remoteBindPoint=

new InetSocketAddress(args[0],

Integer.valueOf(args[1]));

/* Create datagram packet for sending message */

DatagramPacket sendPacket=

new DatagramPacket(MSG.getBytes(),

MSG.length(),

remoteBindPoint);

/* Create datagram packet for receiving echoed message */

DatagramPacket receivePacket= new DatagramPacket(buf, buf.length);

/* Send and receive message*/

socket.send(sendPacket);

socket.receive(receivePacket);

/* Compare sent and received message */

String receivedString=

new String(receivePacket.getData(),

receivePacket.getOffset(),

receivePacket.getLength());

if (receivedString.compareTo(MSG) == 0)

System.out.printf("%d bytes sent and received ", receivePacket.getLength());

else

System.out.printf("Sent and received msg not equal! ");

socket.close();

}

}

/*

UDPEchoServer.java

A simple echo server with no error handling

*/

package dv201.labb2;

import java.io.IOException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetSocketAddress;

import java.net.SocketAddress;

public class UDPEchoServer {

public static final int BUFSIZE= 1024;

public static final int MYPORT= 4950;

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

byte[] buf= new byte[BUFSIZE];

/* Create socket */

DatagramSocket socket= new DatagramSocket(null);

/* Create local bind point */

SocketAddress localBindPoint= new InetSocketAddress(MYPORT);

socket.bind(localBindPoint);

while (true) {

/* Create datagram packet for receiving message */

DatagramPacket receivePacket= new DatagramPacket(buf, buf.length);

/* Receiving message */

socket.receive(receivePacket);

/* Create datagram packet for sending message */

DatagramPacket sendPacket=

new DatagramPacket(receivePacket.getData(),

receivePacket.getLength(),

receivePacket.getAddress(),

receivePacket.getPort());

/* Send message*/

socket.send(sendPacket);

System.out.printf("UDP echo request from %s", receivePacket.getAddress().getHostAddress());

System.out.printf(" using port %d ", receivePacket.getPort());

}

}

}