Hi all,

I could really use some help with a multithreaded server/client application that I'm building. I'm first experimenting with basic concepts and then am going to implement the results within a larger application. However, I find myself stuck on a particular issue. Initially, I transfer a file from the client to the server. This works fine. However, once this transfer has been completed I wish to send additional messages between server and client. This is where the problem lies as the client and server both hang on their respective sides. I really don't know how to resolve this problem. I did implement closing the socket and reopening another and this worked fine when running a single client. However, when running multiple clients I encountered problems that are self-explanatory. So I need another solution that doesn't involve closing and reopening the socket.

Here is my server code:

PHP Code:
import java.io.*;
import java.net.*;
public class Provider implements Runnable{
    ServerSocket server;
    BufferedInputStream bis;
    BufferedOutputStream bos;
    InputStreamReader isr;
    Socket sock;
    int in;
    PrintWriter outputStream;
    int count = 0;
    public void run()
    {
        outputStream = null;
        try{
            server = new ServerSocket(1517);
            while (true)
            {
                sock = server.accept();
                ClientThread c = new ClientThread(sock,count);
                Thread t = new Thread(c);
                t.start();
            }    
        }
        catch (Exception e)
        {
            System.out.println(e.getMessage());
        }
        finally {
            try {
                sock.close();
                server.close();
            }
            catch (Exception e)
            {
                System.out.println(e.getMessage());
            }
        }
    }

    public static void main(String args[])
    {
        Provider Server = new Provider();
        Server.run();
    }
} 
Here is my ClientThread code:
PHP Code:
import java.io.*;
import java.net.*;
public class ClientThread implements Runnable {
    ServerSocket server;
    BufferedInputStream bis;
    BufferedOutputStream bos;
    InputStreamReader isr;
    Socket sock;
    int in;
    PrintWriter outputStream;
    int ID = 0;
  
   ClientThread(Socket s, int ID){
        this.sock = s;
        this.ID = ID;
    }
    
    public void run() {
        try {
                bis = new BufferedInputStream(sock.getInputStream());
                bos = new BufferedOutputStream(new FileOutputStream("C:/Amanda_test/test"));
                byte[] byteArray = new byte[6022386];
                while ((in = bis.read(byteArray)) != -1)
                {
                    bos.write(byteArray,0,in);
                }
            bos.flush();
                        BufferedReader input = new BufferedReader(
                        new InputStreamReader(
                            sock.getInputStream()));
            PrintWriter out = new PrintWriter(sock.getOutputStream(), true);
                        // not sure whether this is necessary
                        // just thought that it would be bad form for the client to wait
                       // for the server to write a message first. I've tried with and
                       // without the readLine(), though, and it makes no difference
                        input.readLine();
                        out.println("success");  // necessary
                        out.flush();
                        out.close();
                        input.close();
            bos.close();
            bis.close();
                        this.sock.close();
        }
        catch (Exception e)
        {
            System.out.println(e.getMessage());
        }
    }
} 
and this is my Client code:

PHP Code:
import java.io.*;
import java.net.*;
public class Requester{
    Socket requestSocket;
    BufferedOutputStream bos;
    BufferedInputStream bis;
    Socket sock;
    int in;
    Requester(){}
    void run()
    {
        try{
            //1. creating a socket to connect to the server
            sock = new Socket("myServer.ac.za", 1517);
            System.out.println("Connected to localhost in port 1517");
            File myFile = new File("F:/Documents.txt");
            bis = new BufferedInputStream(new FileInputStream(myFile));
            bos = new BufferedOutputStream(sock.getOutputStream());
            byte[] byteArray = new byte[(int)myFile.length()];
            System.out.println((int)myFile.length());
            while((in = bis.read(byteArray))!= -1)
            {
                bos.write(byteArray,0,in);
            }
            bos.flush();
                        BufferedReader input = new BufferedReader(
                        new InputStreamReader(
                            sock.getInputStream()));
            PrintWriter out = new PrintWriter(sock.getOutputStream(), true);
                        // not sure whether this is necessary
                        // just thought that it would be bad form for the client to wait
                       // for the server to write a message first. I've tried with and
                       // without the println(), though, and it makes no difference
                        out.println("maybe no reason for this");
                        String word = input.readLine();  // necessary
                        out.flush();
                        out.close();
                        input.close();
            bos.close();
            bis.close();
            sock.close();
        }
        catch (Exception e)
        {
            System.out.println(e.getMessage());
        }
    }
} 
Help would be greatly appreciated!

Thanks.