Question

Design and implement a Java program that enables two users to chat. Using GUIs implement one user as the server and the other as the client. The sever has two text areas: one for entering text and the other (noneditable) for displaying text received from the client. The client has two text areas: one for receiving text from the server and the other for entering text. When the user presses the enter key, the current line is sent to the server or client.

Answer 1

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.Socket;

public class TCPClient {

   public static void main(String argv[]) throws Exception {
       String word;
       String wordsent;
     
       BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
       Socket clientSocket = new Socket("localhost", 6789);
       while (true) {
           DataOutputStream outToServer = new DataOutputStream( clientSocket.getOutputStream());
           BufferedReader inFromServer = new BufferedReader( new InputStreamReader( clientSocket.getInputStream()));
           word = inFromUser.readLine();
           outToServer.writeBytes(word + '\n');
           if (word.equals("EXIT")) {
               break;
           }
           wordsent = inFromServer.readLine();
           System.out.println("FROM SERVER: " + wordsent);
       }
       clientSocket.close();
   }
}

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.logging.Level;
import java.util.logging.Logger;

public class TCPServer {

   public static void main(String argv[]) throws Exception {
       ServerSocket socket = new ServerSocket(6789);
       Responder h = new Responder();
       while (true) {
           Socket connSocket = socket.accept();
           Thread t = new Thread(new ChatServer(h,connSocket));
           t.start();
       }  
   }
}

class ChatServer implements Runnable {

   Responder resp;
   Socket socketConnection;

   public ChatServer(Responder r, Socket connSocket) {
           this.resp = r;
           this.socketConnection = connSocket;
   }

   @Override
   public void run() {
       while (resp.responderMethod(socketConnection)) {
           try {
               Thread.sleep(2000);
           }
           catch (InterruptedException ex) {
               ex.printStackTrace();
           }
       }
       try
       {
           socketConnection.close();
       }
       catch (IOException ex) {
           System.out.println("Exception occured: "+ex.toString());
       }
   }

}

class Responder {
   String word;
   BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   synchronized public boolean responderMethod(Socket connectionSocket) {
       try {
           BufferedReader inFromClient = new BufferedReader( new InputStreamReader( connectionSocket.getInputStream()));
           DataOutputStream outToClient =new DataOutputStream(connectionSocket.getOutputStream());
           String clientSentence = inFromClient.readLine();
           if (clientSentence == null || clientSentence.equals("EXIT")) {
               return false;
           }
           if (clientSentence != null) {
               System.out.println("client : " + clientSentence);
           }
           word = br.readLine() + "\n";
           outToClient.writeBytes(word);
           return true;
       }
       catch (SocketException e) {
           System.out.println("Disconnected from the server");
           return false;
       }
       catch (Exception e) {
           e.printStackTrace();
           return false;
       }
   }
}