TCP客户端套接字。 连接并等待输入流

Question

I have a wifi sd card which sends me TCP packages with information about new images on the memory after I shoot a photo with the camera.

On the terminal I can read the inputstream with this netcat command. netcat connects to ip 192.168.11.254 and listen on port 5566. the second line is the image path which I receive.

$ nc 192.168.11.254 5566
>/mnt/sd/DCIM/109_0302/IMGP0101.JPG

On my app I have a Java client socket which is connected to the same ip and port. But I don't receive the inputstream like in netcat, nothing happens.

void startListenForTCP (){
    Thread TCPListenerThread = new Thread(new Runnable() {
        @Override
        public void run() {

            Boolean run = true;
            String serverMessage = null;
            InetAddress serverAddr = null;

            try {
                serverAddr = InetAddress.getByName("192.168.11.254");
                Socket clientSocket = new Socket(serverAddr, 5566);

                try{
                    BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

                    while (run) {
                        serverMessage = in.readLine();
                        mHandler.post(new DisplayToast(context, "TCP : " + serverMessage));
                    }

                } catch(UnknownHostException e) {
                    mHandler.post(new DisplayToast(context, "UnknownHostException"));

                } catch(IOException e) {
                    mHandler.post(new DisplayToast(context, "IOException"));
                } finally {
                    clientSocket.close();
                }

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

        }
    });
    TCPListenerThread.start();
}

Answer 1

try this may it works

Step 1

Remove these two lines:

serverAddr = InetAddress.getByName("192.168.11.254");
Socket clientSocket = new Socket(serverAddr, 5566);

Add this line:

Socket clientSocket = new Socket("192.168.11.254", 5566);

Step 2

Remove this code:

try {
    BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
    while (run) {
        serverMessage = in.readLine();
        mHandler.post(new DisplayToast(context, "TCP : " + serverMessage));
    }
}

Add this code:

try {
    char[] buffer = new char[2048];
    int charsRead = 0;
    BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
    while ((charsRead = in.read(buffer)) != -1) {
        String message = new String(buffer).substring(0, charsRead);
        Log.e("In While", "msg :"+message);   
    }
}

Answer 2

The javadoc of BufferedReader.readLine() states:

Read a line of text. A line is considered to be terminated by any one of a line feed ('\\n'), a carriage return ('\\r'), or a carriage return followed immediately by a linefeed.

If the card doesn't send some kind of end of line, this method will never return. Try to read directyl from clientSocket.getInputStream() . This doesn't do any buffering.