Java无法获得客户端或服务器响应

Question

I'm from Poland, so I'm sorry for any mistakes.
I've coding for a while a small server and client connection, when I stopped on annoying problem. When I send from client to server information (String), server can get it, but can't respone to it.

Here it is code.

Client

private static Socket socket;

public static void main(String args[]){
    try{
       String host = "localhost";
       int port = 25002;
       InetAddress address = InetAddress.getByName(host);
       socket = new Socket();
       socket.connect(new InetSocketAddress(host, port), 5000);

       //Send the message to the server
       System.out.println("< "+sendMessage(socket));
       //socket.shutdownOutput();
       System.out.println("> "+getMessage(socket));
   }catch (SocketTimeoutException e){
      System.out.println(e.getMessage()); // changed
   }catch (IOException e){
      System.out.println(e.getMessage()); // changed
   }catch (IllegalBlockingModeException e){
      System.out.println(e.getMessage()); // changed
   }catch(IllegalArgumentException e){
      System.out.println(e.getMessage()); // changed
   }finally{
      //Closing the socket
      try{
         socket.close();
      }catch(Exception e){
         System.out.println(e.getMessage()); // changed
      }
   }
}

public static String sendMessage(Socket client){
    try {
        String message = "test";
        PrintWriter writer = new PrintWriter(client.getOutputStream(), true);
        writer = new PrintWriter(client.getOutputStream(), true);
        writer.print(message);
        writer.flush();
        writer.close();
        return message;
     } catch (IOException e) {
        System.out.println(e.getMessage()); // changed
        return "false";
     }
}

public static String getMessage(Socket client){
            try {
                BufferedReader socketReader = new BufferedReader(new InputStreamReader(client.getInputStream()));
                return socketReader.readLine();
            } catch (IOException e){
                System.out.println(e.getMessage()); // changed
                return "false";
            }
        }

And.. server

public class kRcon{
        private static Socket socket;
        private static ServerSocket serverSocket;
        private static Thread u;

        private static class Server extends Thread {
                public void run() {
                        int port = 25002;
                        try {
                            serverSocket = new ServerSocket(port);
                        } catch (IOException e1) {
                            // TODO Auto-generated catch block
                            e1.printStackTrace();
                        }
                        while(true) {
                          try {
                             socket = serverSocket.accept();
                             BufferedReader socketReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                             BufferedWriter socketWriter = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
                             String str = socketReader.readLine();
                        socketReader.close();
                             System.out.println(str);
                             socketWriter.write("test");
                             socketWriter.flush();
                             socketWriter.close();
                          }
                        }catch (IOException e1) {
                            e1.printStackTrace();
                        }
               }
         public static void init(){
         try {
            u = new Server();
            u.setName("Server");
            u.start();
        } catch (IOException e) {
            System.out.println(e.getMessage()); // changed
        }
    }
}

Results
If, I start server first all looks nice. So, I start the client with parametr "test", nad output to console is:

< test
Socket is closed // changed

On server-side in console I have:

"test"
Socket is closed // changed

I tried to shutdown inputs and outputs and dosen't work.. I don't know to do now. Please help :c

Edited 2015-04-03
I've changed lines with comment "changed".

For Google, and readers To fix problem, don't close StreamReaders nad StreamWriters on client's sides. Thanks to EJP , for help!
Greetings from Poland.

Answer 1

When you get an exception, print it. Don't just throw away all that information. And don't return magic Strings either. In this case you should have let the exception propagate. If you had done all that you would have seen the exception SocketException: socket closed being thrown by getMessage(), and you would have had something concrete to investigate, instead of a complete mystery.

It is caused by closing the PrintWriter in sendMessage(). Closing either the input or output stream of a socket closes the other stream and the socket.