Socket communication between applet and an AP on simulastor

Question

Hi!
I implemented my system under Server/Client model.
The server is running in a Set-Top-Box simulator, which
creates a ServerSocket on port 9190.
The client is an applet and using the following codes to connect to server:
==========================================
Socket socket = new Socket("127.0.0.1", 9190)
InputStream in = socket.getInputStream();
OutputStream out = socket.getOutputStream();
==========================================
When I start the applet, no exceptions are thrown,
and objects socket, in and out are not null.
But when I was trying to send a string to server,
==========================================
out.write("a string".getBytes());
==========================================
nothing happened. Server didn't get anything.
What's wrong? How can I solve this?

Answer 1

First of all "nothing happend" is something you tell the DELL helpdesk.
This is a developer forum.
My guess is you are using somthing of a in.readLine() on the server and since the
client doesn't sent a linebreak it will hang there.
Or the client gets an AccessControlException that you silently catch and therefore get
no exception. Allthough the InputStream would be declared in the try block (according
to posted code) and can not be checked for beeing null in the catch (out of scope).
Here is some sample code of client and server, try to implement the run method in
your client and run both appTest and applet on the local machine (http://127.0.0.1).
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class appTest implements Runnable {
     public appTest() {
          new listner().start();
          new Thread(this).start();
     // main program
     public static void main(String argv[]) throws Exception {
          new appTest();
     public void run() {
          // the client
          try {
               Socket s = new Socket("127.0.0.1", 9190);
               // if multiple messages are to be sent and received
               // this is where you start a new thread
               byte b[];
               OutputStream out = s.getOutputStream();
               InputStream in = s.getInputStream();
               String message = "hello from client";
               int messageLength = message.getBytes().length;
               // writing the length of the message
               out.write(new Integer(messageLength).byteValue());
               b = message.getBytes();
               // writing the message
               out.write(b);
               // reading the length of the message and setting the byte array to
               // it
               b = new byte[in.read()];
               in.read(b);
               // receiving the message
               System.out
                         .println("received massage from server: " + new String(b));
               out.close();
               in.close();
          } catch (Exception e) {
               e.printStackTrace();
     class listner extends Thread {
          public void run() {
               try {
                    ServerSocket srv = new ServerSocket(9190);
                    while (true) {
                         try {
                              System.out.println("before accepting a client");
                              Socket s = srv.accept();
                              System.out.println("after accepting a client");
                              // if multiple messages are to be sent and received
                              // this is where you start a new thread
                              byte b[];
                              OutputStream out = s.getOutputStream();
                              InputStream in = s.getInputStream();
                              // reading the length of the message and setting the
                              // byte array to
                              // it
                              b = new byte[in.read()];
                              in.read(b);
                              // receiving the message
                              System.out.println("received massage from client:"
                                        + new String(b));
                              System.out.println("sending message from server:");
                              String message = "hello from server";
                              int messageLength = message.getBytes().length;
                              // writing the length of the message
                              out.write(new Integer(messageLength).byteValue());
                              b = message.getBytes();
                              // writing the message
                              out.write(b);
                              out.close();
                              in.close();
                         } catch (Exception ex) {
                              ex.printStackTrace();
               } catch (Exception e) {
                    e.printStackTrace();
}