发送实时流数据时套接字连接丢失

Question

I'm struggling here...

I'm trying to determine if data was successfully sent to the server through a TCP socket using the OutputStream object. For testing on emulator socket communications is loss after 30 sec. For write data OutputStream.write(); its doesn't throw an exception , and local server continuously running its not crashing, only tcp socket connection is loss after some time. All the methods in the socket class return as though the socket is active and working. Is there anything I'm doing wrong here? Is there any socket implementation or stream implementation I can use to get an exception or error when the stream/ socket doesn't actually send the data in the buffer? Also setting setSoTimeout() on the socket doesn't seem to do anything.

Please guide me...

Here is my code:

private void sendRec() {
    int lstream;
    int port = 1012;
    byte[] byterecv = new byte[1040];

    while (true) {
        System.out.println("POOL-2");
        synchronized (recSendThread) {
            try {
                recSendThread.wait(20);
            } catch (InterruptedException e) {
            }
        }

        if (stopcall == true) {
            // break;
        }

        try {
            // Provides a client-side TCP socket
            Socket clientRec = new Socket();

            // serverSocket = new ServerSocket(port);
            // serverSocket.setSoTimeout(5000);

            // Connects this socket to the given remote host address and
            // port
            clientRec.connect(new InetSocketAddress("192.168.1.36", port));

            System.out.println("Just connected to "
                    + clientRec.getRemoteSocketAddress());
            System.out.println("SENTS Rec BEFORE");

            // output streams that write data to the network
            OutputStream outToServerRec = clientRec.getOutputStream();
            DataOutputStream outStreamRec = new DataOutputStream(
                    outToServerRec);

            outStreamRec.write(bData);
            System.out.println("SENTS Rec AFTER");

            // input streams that read data from network
            InputStream inFromServerRec = clientRec.getInputStream();
            // clientRec.setSoTimeout(5000);
            DataInputStream inStreamRec = new DataInputStream(
                    inFromServerRec);
            while ((lstream = inStreamRec.read(byterecv)) != -1) {
                System.out.println("startrec bytearray -- "
                        + byterecv.length);
                bos1.write(byterecv, 0, lstream);
            }

            inStreamRec.close();// for closing dataouputstream
            clientRec.close();// for closing socket connection
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}





Here is my receiver and player code..



  /**
   * start receiving the voice data from server
   * */
       protected void startplay() {
    System.arraycopy(frndid, 0, playByteData, 0, 4);
    System.arraycopy(userid, 0, playByteData, 4, 4);

        ByteBuffer.wrap(sessionid).order(ByteOrder.LITTLE_ENDIAN).asIntBuffer().
            put(call_sessionid);
    System.arraycopy(sessionid, 0, playByteData, 8, 4);
    int lstream;
    int port = 1014;
    while (true) {
        System.out.println("POOL-3");
        try {
            if (stopcall == true) {
                System.out.println("BREAKEDDDD1111");
                //break;
            }
            // Host name
            // port++;
            InetAddress addressPlay = InetAddress.getByName("192.168.1.36");
            // Creates a new streaming socket connected to the target host
            Socket clientPlay = new Socket(addressPlay, port);
            System.out.println("Just connected to play : " + 
                                                clientPlay.getRemoteSocketAddress());
            System.out.println("SENTS Play BEFORE");

            // output streams that write data

            OutputStream outToServer = clientPlay.getOutputStream();
            DataOutputStream outStreamPlay = new DataOutputStream(outToServer);
            outStreamPlay.write(playByteData);


            System.out.println("SENTS Play after");

            // input streams that read data
            InputStream inFromServerPlay = clientPlay.getInputStream();
            DataInputStream inStreamPlay = new DataInputStream(inFromServerPlay);
            //clientPlay.setSoTimeout(5000);
            while ((lstream = inStreamPlay.read(byteArray)) != -1) {
                System.out.println("startplay() bytearray -- " + 
                                                          byteArray.length);
                bos.write(byteArray, 0, lstream);
            }

            inStreamPlay.close();
            clientPlay.close();// for closing play socket connection

            responseBuffer = bos.toByteArray();
            System.out.println("BAOSSIZE " + bos.size());
            bos.reset();
            bos.flush();
            bos.close();
            playing = true;
            System.out.println("res length -- " + responseBuffer.length);
            rcvbb=ByteBuffer.wrap(responseBuffer).order(ByteOrder.LITTLE_ENDIAN).
                                                    asShortBuffer().get(playShortData);

              playVoiceReceived();// plays received data

            } catch (ParseException e) {
            e.printStackTrace();
            } catch (IOException e) {
            e.printStackTrace();
        }
    }
    }

  /**
   * start playing received the voice data from server
    * */
     public void playVoiceReceived() {

    System.out.println("POOL-4");
      try {
        if (at != null) {
            if (at.getPlayState() != AudioTrack.PLAYSTATE_PLAYING) {
                at.play();// starts playing
            } else {
                System.out.println("Play BEFORE WRITE");
                // Writes the audio data to the audio hardware for playback.
                at.write(playShortData, 0, BufferElements2Play);
                System.out.println("Play AFTER WRITE");
                at.flush();
            }
        }
          } catch (Exception e) {
        e.printStackTrace();
      }
    }

Answer 1

The socket has sent the data ... to the local socket send buffer. What happens after that is up to the local TCP stack, the network, the remote TCP stack, and the remote application. If you want to know whether the remote application got the data, it will have to send you a reply.

Answer 2

Operator write does not check whether data was delivered because otherwise it would have to wait for too long time. If network connection is actually down, TCP layer of operating system, will try to send data anyway, but will detect problems somewhat later, ie 1 minute later, because it will not receive acknowledgement messages from the opposite side. It will then try to resend data several times, see that problem persists and only then will report exception condition on the socket. To know that socket is in exception condition, you need to perform some operator on socket, ie another write attempt. Try doing write in a loop like this:

while (true) { outStreamRec.write (data); Thread.sleep (1000L); }

It should throw an error about 2 minutes after network will be down.

Note, that in opposite to write operation, operation connect is synchronous, so it actually waits for response from the opposite side, and if there is not respose, it will throw an exception.