Question

I have a problem with the code for my project. I need the two clients to be able to receive the messages but the code I have done only the server receives the messages. I need the clients to be able to communicate with each other directly not throught the server.

The requirements of this "local chat" program must meet are:

1. The chat is performed between 2 clients and a server.

2. The server will first start up and choose a port number. Then the server prints out its IP address and port number.

3. The client then will start up and create a socket based on the information provided by the server.

4. Now the client and the server can chat with each other by sending messages over the network.

5. The client/server MUST be able to communicate with each other in a continuous manner. (e.g. One side can send multiple messages without any replies from the other side)

6. There is no requirement on what language you use to implement this project, but your program should call upon the socket API for UDP to realize the functionality.

7. You should demonstrate your project using two machines (one for the client and one for the server. Pick your virtual machine as the client to communicate with your actual machine, which is server in our project).

8. You need to open at least 2 cmd window in your virtual machine to demonstrate multiple machine communicate with your server machine (actual machine)

My Code

UDPServer.java

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class UDPServer {
   public static void main(String args[]) throws Exception{
       int serverport=6789;
       int clientport=1234;
       byte[] receiveData = new byte[1024];
       byte[] sendData = new byte[1024];
       DatagramSocket serverSocket = new DatagramSocket(serverport);
       System.out.println("SERVER READY");
       while(true){
       DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
       serverSocket.receive(receivePacket);
       String msg = new String(receivePacket.getData()).trim();
       System.out.println("Message from CLIENT with ID:"+msg);
        InetAddress IPAddress = receivePacket.getAddress();
       int port = receivePacket.getPort();
       String returnMsg = "Thanks. Received your message!";
       sendData = returnMsg.getBytes();
       DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);
       serverSocket.send(sendPacket);
       }
   }
}

UDPClient.java

package socket;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class UDPClient {
   public static void main(String args[]) throws Exception{
       int serverport=6789;
       int clientport=1234;
       byte[] sendData = new byte[1024];
       byte[] receiveData = new byte[1024];       
       BufferedReader inFromUser = new BufferedReader(   new InputStreamReader(System.in));
       String clientId;
       System.out.println("Enter your ID:");
       clientId = inFromUser.readLine();
       while(true) {
           System.out.println("Enter your message:");
           String sentence = inFromUser.readLine();
          
           DatagramSocket clientSocket = new DatagramSocket();
           InetAddress IPAddress = InetAddress.getByName("localhost");
           sendData = (clientId+":"+sentence).getBytes();
           DatagramPacket sendPacket =
                   new DatagramPacket(sendData, sendData.length, IPAddress, serverport);
           clientSocket.send(sendPacket);
           DatagramPacket receivePacket =
                   new DatagramPacket(receiveData, receiveData.length);
           clientSocket.receive(receivePacket);
           String receivedMsg = new String(receivePacket.getData()).trim();
           System.out.println("FROM SERVER:" + receivedMsg);
           clientSocket.close();
       }
   }
}

Answer 1

UDPClient.java

import java.io.*;
import java.net.Socket;

public class ChatClient {

static Socket s;

static int port;

static String name;

public static void main(String[] args) {

Receivemsg1 receive = new Receivemsg1();
Sendmsg1 send = new Sendmsg1();

Thread receiver = new Thread(receive);
Thread sender = new Thread(send);

try{

port = Integer.parseInt(args[2]);
s = new Socket(args[1], port);
name = args[0];
System.out.println("Connected to: " + s.getRemoteSocketAddress());
System.out.println("Welcome " + name + "!");
System.out.println("** Note: Type 'bye' and press Enter to disconnect **");
   System.out.println(">You are ready to start your chat!\n");

receiver.start();
sender.start();

}catch(IOException e){
e.printStackTrace();
}
}
}

class Sendmsg1 implements Runnable {
@Override
public void run() {
String input;
PrintWriter out = null;
  
try {
out = new PrintWriter(ChatClient.s.getOutputStream(), true);
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
try {
while (!(input = br.readLine()).equals("bye")){
out.println(input);
}
out.println("Client disconnected");
ChatClient.s.close();
} catch (IOException e) {
System.out.println("Disconnected");
}
}
}

class Receivemsg1 implements Runnable {
@Override
public void run() {
String line;
BufferedReader in = null;
try {
in = new BufferedReader(new InputStreamReader(ChatClient.s.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
try {
while((line = in.readLine()) != null) {
if(line.equals("Server disconnected")){
System.out.println("> Server: bye");
System.out.println(line);
break;
}
  
}
} catch (IOException e) {
System.out.println("Disconnected");
}
}
}

UDPServer.java

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class ChatServer
{

static int port;
static ServerSocket ss;
static Socket s;

public static void main(String[] args)
{

Receivemsg receive = new Receivemsg();   
Sendmsg send = new Sendmsg();

Thread receiver = new Thread(receive); //Creating thread variables
Thread sender = new Thread(send);

try{

port = Integer.parseInt(args[0]);
ss = new ServerSocket(port); //connected to given port number
System.out.println("Server Started with port: " + ss.getLocalPort());
s = ss.accept();
System.out.println("Connection Established with client: " + s.getRemoteSocketAddress());
System.out.println("** Note: Type 'bye' and press Enter to disconnect **");
   System.out.println(">You are ready to start your chat!\n");
receiver.start(); //receiver thread invoked
sender.start(); //sender thread invoked
}
catch(IOException e)
{
e.printStackTrace();
}
}
}

class Sendmsg implements Runnable {
@Override
public void run() {
String input;
PrintWriter out = null;
  
try {
out = new PrintWriter(ChatServer.s.getOutputStream(), true); //store what is to be sent as output through port
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
try {
while (!(input = br.readLine()).equals("bye")){
out.println(input);
}
out.println("Server disconnected");
ChatServer.s.close();
} catch (IOException e) {
System.out.println("Disconnected");
}
  
}
}

class Receivemsg implements Runnable {
@Override
public void run() {
String line;
BufferedReader in = null;
try {
in = new BufferedReader(new InputStreamReader(ChatServer.s.getInputStream())); //read the message from the socket
} catch (IOException e) {
e.printStackTrace();
}
try {
while((line = in.readLine()) != null) {
if(line.equals("Client disconnected")){
System.out.println("> Client: bye");
System.out.println(line);
break;
}
  
      
}
} catch (IOException e) {
System.out.println("Disconnected");
}
}
}

Check this! This needed lot of work and finally here! :-)