MultiThreadChatClient.java

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

public class MultiThreadChatClient implements Runnable 
{
  private static Socket clientSocket = null;// The client socket  
  private static PrintStream os = null;// The client socket 
  private static DataInputStream is = null; // The input stream
  private static BufferedReader inputLine = null;
  private static boolean closed = false;
  
  public static void main(String[] args) 
  {  
    int portNumber = 2222;  // The default port.    
    String host = "localhost";// The default host.
    if (args.length < 2) 
	   System.out.println("Usage: java MultiThreadChatClient <host> <portNumber>\n"+ "Now using host=" + host + ", portNumber=" + portNumber);
    else 
	{
      host = args[0];
      portNumber = Integer.valueOf(args[1]).intValue();
    }
	 //Open a socket on a given host and port. Open input and output streams.
    try 
	{
      clientSocket = new Socket(host, portNumber);
      inputLine = new BufferedReader(new InputStreamReader(System.in));
      os=new PrintStream(clientSocket.getOutputStream());
      is=new DataInputStream(clientSocket.getInputStream());
    }
	catch (UnknownHostException e)
	{
      System.err.println("Don't know about host " + host);
    }
	catch (IOException e) 
	{
      System.err.println("Couldn't get I/O for the connection to the host "+ host);
    }
    // If everything has been initialized then we want to write some data to the socket we have opened a connection to on the port portNumber.
    if (clientSocket != null && os != null && is != null) 
	{
      try 
	  {      
        new Thread(new MultiThreadChatClient()).start();// Create a thread to read from the server.
        while (!closed) 
		{
          os.println(inputLine.readLine().trim());
        }
        // Close the output stream, close the input stream, close the socket.
        os.close();
        is.close();
        clientSocket.close();
      } 
	  catch (IOException e)
	  {
        System.err.println("IOException:  " + e);
      }
    }
  }

//Create a thread to read from the server. 
 public void run() {
    //Keep on reading from the socket till we receive "Bye" from the server. Once we received that then we want to break.
    String responseLine;
    try {
      while ((responseLine = is.readLine()) != null) 
	  {
        System.out.println(responseLine);
        if (responseLine.indexOf("*** Bye") != -1)
          break;
      }
      closed = true;
    } 
	catch (IOException e) 
	{
      System.err.println("IOException:  " + e);
    }
  }
}