问Android上的Java套接字，通过3G互联网全球ip连接

EN

java.net.SocketException: recvfrom failed: ETIMEDOUT (Connection timed out)

    private ServerSocket _mainServer = null;

    private void initServer() {

        try {
                        //port I use here is arbitrary: 8081
            _mainServer = new ServerSocket(CONNECT_SOCKET_PORT);
        } catch (IOException e) {
            Log.w("ServerSocket", e.toString());
            e.printStackTrace();
        }
    }

        while (running) {
            GuestConnect ssc = new GuestConnect(_mainServer.accept());
            ssc.setListener(this);
            ssc.startConnection();

            _clientSockets.add(ssc);

            performGuestAdded("bra!");
        }

public void onMessageReceived(TBTGuestConnect sender, String message) {
    for(TBTGuestConnect guestConnect : _clientSockets)
        if(guestConnect != sender)
            guestConnect.sendMessage(message);
}

public class GuestConnect {


   private StringBuilder _currentMessage;
   private BufferedReader _is;
   private PrintStream _os;
   private Socket _clientSocket = null;

   private String _hostname;

   private boolean _running = false;

   public GuestConnect(String hostname) {
    _hostname = hostname;

    _currentMessage = new StringBuilder();
   }

private void initSocket() {

    if(_clientSocket==null)
    {
        // Try to open a server socket on given port
        // Here is the fail when I called it from another device
        try {
            _clientSocket = new Socket(_hostname, ServerConnect.CONNECT_SOCKET_PORT);
        } catch (IOException e) {
            Log.w("GuestSocket", e.toString());
        }
    }

    // Create a socket object from the ServerSocket to listen and accept
    // connections.
    // Open input and output streams
    try {
        _is = new BufferedReader(new InputStreamReader(_clientSocket.getInputStream()));
        _os = new PrintStream(_clientSocket.getOutputStream());


    } catch (IOException e) {
        Log.w("GuestSocket", e.toString());

    }
}

    initSocket();

    _running = true;

    performConnectionStarted();
    try {
        while (_running) {
            String received = _is.readLine();
            _currentMessage.append(received);
            if (received.contains(ServerConnect.CONNECT_SOCKET_MESSAGE_END)) {
                String finalMsg = _currentMessage.toString().substring(0, _currentMessage.lastIndexOf(ServerConnect.CONNECT_SOCKET_MESSAGE_END));
                performMessageReceived(finalMsg);
                _currentMessage.setLength(0);
            }

        }
    } catch (IOException e) {
        Log.w("GuestSocket", e.toString());
        performError(e);
    } finally {

        try {
            _os.close();
            _is.close();
            _clientSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
            performError(e);
        }

        _clientSocket = null;
    }

public void sendMessage(String toSend) {
    if (_running)
        _os.println(toSend+ServerConnect.CONNECT_SOCKET_MESSAGE_END);
    else
        throw new IllegalStateException("Send message : Connection isn't started !");
}