Accepting connection from multiple client

Question

Hi, i try to open a port on the server and allows others client to connect to this port and sent in data. It works well when it's 1 server to 1 client relationship. But when i turn on 1 server to many client connection where all the client will connect at the same time... none of the client data were capture in the server. Here is my code :
Server code:
static class Listener extends Thread
          public void run()
               ServerSocket svrSocket;
               Socket soc;
               try
                    svrSocket = new ServerSocket(20);
                    System.out.println("---------------------------------------");
                    soc = svrSocket.accept();
                    System.out.println("---------------------------------------");
                    BufferedReader in = new BufferedReader(new InputStreamReader(soc.getInputStream()));
                    String strTest;
                    while((strTest = in.readLine()) != null)
                         System.out.println("SEE THIS !!!!!!!!!!!!! " + strTest);
               catch(Exception e)
                    e.printStackTrace();
Client code:
socClient = new Socket("10.1.8.101", 4444);
outPrintWriter = new PrintWriter(socClient.getOutputStream(), true);
outPrintWriter.println(strWrite);
Can anyone help me??? IT"S URGENT....
THANKS

Answer 1

Your code will only handle one connection at a time currently. To handle more connections it needs to be reorganized, see below. Also, you may be having a problem with binding port 20 in your server and trying to connect to port 4444 in your client. These ports obviously have to be the same or its never going to work at all! :-)
Without getting into thread pools and stuff, this is a sample of how you might want to organize your server.
import java.net.*;
import java.io.*;
import java.util.*;
public class SocServ implements Runnable {
    // running flag set to false to stop server.
    public static boolean isRunning=true;
    // set of servicing threads, if needed.
    private static Set servicers = new HashSet();
    public void run() {
        ServerSocket svrSocket;
        Socket soc;
        Thread t;
        // open the server socket, error if port is in use, etc.
     try {
            svrSocket = new ServerSocket(4096);
            // accept connections, and start new SocServicer threads.
            while (SocServ.isRunning) {
                soc = svrSocket.accept();
                t = new Thread(new SocServicer(soc));
          SocServ.servicers.add(t);
                t.start();
            // server finished, close socket
            svrSocket.close();
        } catch (IOException e) { e.printStackTrace(); }
import java.net.*;
public class SocServicer implements Runnable {
     // socket connection being serviced...
     Socket s;
     public SocServicer(Socket soc) { s=soc; }
     public void run() {
          if (s==null) { return; } // for sanity
          * Do all the interaction with each socket here.
}The idea is to run one thread that listens for connections and then spawn new threads to process each connection. This way one connection does not have to wait for the previous one to finish. For a serious application you will probably want to do some more careful management of the SocServicer threads [because each thread eats up memory & resources].