Question

Problem 3

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.

Answer 1

implemented using the java programming .server side programming

vmt un 3 import java.io.*; import java.util.*; import java.net.*; 7 public class client 8- 9. public static void main (String[] args) { 10 11. try{ 12 Socket s=new Socket("localhost",4321); 13 DataInputStream is=new DataInputStream(s.getInputStream()); 14 String str=(String)is.readUTF(); 15 System.out.println("response= "+str); 16 s.close(); }catch(Exception e) { System.out.println(e); } 17 18

2 3 4 import java.io.*; import java.util.*; import java.net.*; 6 public class Server 7-{ public static void main (String[] args) { Socket socket; while(true) try{ ServerSocket ss = new ServerSocket(4321); socket = ss.accept(); // server recieves connection and accept it System.out.println("new client request received"); DataInputStream is = new DataInputStream( socket.getInputStream()); //for DataOutputStream os = new DataOutputStream( socket.getOutputStream()); // clientHandler handler = new clientHandler(socket,is,os); Thread thread = new Thread (handler); //client handled separately using tl thread.start():

thread.start(); os.writeUTF("hello client"); //server sends hello to client thread.interrupt(); //client thrread closed after responsing 30 catch(Exception ex) } { 31 32 33 } 35 } 36 37 } 38 39 40 class ClientHandler implements Runnable { Scanner scn = new Scanner(System.in); 41 42 43 44 final DataInputStream is; final DataOutputStream os; Socket socket; 45 clientHandler(Socket socket, DataInputStream is, DataOutputStream os) 46 47 - { 48 49 this.socket = socket; 50 51 this.is = is;

this.is = is; this.os = os; public void run() { String msgreceived; try { msgreceived = is.readUTF(); //message received by client System.out.println("echo: "+msgreceived); } catch(Exception e) { try{ this.is.close(); this.os.close(); catch(IOException ex)

J 74 75 catch(IOException ex) 76 77 ex.printStackTrace(); 84 85