Thread: simple Java chatroom

Quite simple I want to create a chatroom that accepts multiple clients all of which can assign their own ID. Whenever they input anything it is sent to all users. Currently I have a echo client server where the client inputs something and it is echoed back. My first question is how do I allow a user to give himself a username? obviously I need a variable somewhere that accepts the name what class do you recommend I put this in? and how would I get the name itself Something like if (theInput.equalsIgnoreCase("username" : ""))

Then all that I need to do is echo what the client says to all clients. I'm at a loss of how to do this so any advice would be much appreciated. Although I've found some tutorials and example code online I don't understand it and I don't feel comfortable using it if I don't understand even if it does work. Thanks

Here is my code: EchoClient

'// echo client
import java.util.Scanner;
import java.io.*;
import java.net.*;
public class EchoClient {
public static void main(String[] args) throws IOException { 
    Socket echoSocket = null;
    //PrintWriter socketOut = null;
    try {
        echoSocket = new Socket("127.0.0.1", 4444); // connect to self at port 4444
        System.out.println("Connected OK");
        Scanner socketIn = new Scanner(echoSocket.getInputStream());  // set up input from socket
        PrintWriter socketOut = new PrintWriter(echoSocket.getOutputStream(), true);    // set up output to socket
        Scanner kbdIn = new Scanner(System.in);     // Scanner to pick up keyboard input
        String serverResp = "";
        String userInput = kbdIn.nextLine();        // get input from the user
 
        while (true) {
            socketOut.println(userInput);                   // send user input to the socket
            serverResp =  socketIn.nextLine();     // get the response from the socket
            System.out.println("echoed back: " + serverResp);   // print it out
            if (serverResp.equals("Closing connection")) { break; } //break if we're done
            userInput = kbdIn.nextLine();   // get next user input
        }
        socketOut.close();
        kbdIn.close();
        socketIn.close();
    }
    catch (ConnectException e) {
        System.err.println("Could not connect to host");
        System.exit(1);
    }
    catch (IOException e) {
        System.err.println("Couldn't get I/O for connection");
        System.exit(1);
    }
    echoSocket.close();
} 
}'
 
EchoServer
 
// multiple (threaded) server
import java.net.ServerSocket;
import java.net.Socket;
public class EchoServerMult {
public static void main(String[] args) throws Exception {
    ServerSocket serverSocket = new ServerSocket(4444);   // create server socket on this machine
    System.err.println("Started server listening on port 4444");
    while (true) {        // as each connection is made, pass it to a thread
        //new EchoThread(serverSocket.accept()).start();  // this is same as next 3 lines
        Socket x = serverSocket.accept();   // block until next connection
        EchoThread et = new EchoThread(x);
        et.start();  
        System.err.println("Accepted connection from client");
    }
}
}
 
EchoThread
 
// thread to handle one echo connection
import java.net.*;
import java.io.*;
import java.util.Scanner;
public class EchoThread extends Thread {
private Socket mySocket = null;
 
public EchoThread(Socket socket) {       // constructor method
    mySocket = socket;
}
public void run() {
    try {
        PrintWriter out = new PrintWriter(mySocket.getOutputStream(), true);
        Scanner in = new Scanner(mySocket.getInputStream());
        String inputLine;
        while (true) {
            inputLine = in.nextLine();      
            if (inputLine.equalsIgnoreCase("Bye")) {
                out.println("Closing connection");
                break;      
            } else {
                out.println(inputLine);
            }
        }
        out.close();
        in.close();
        mySocket.close(); 
    } catch (Exception e) {
        System.err.println("Connection reset");   // bad error (client died?)
    }
}
}