Question

我使用这些代码在设备之间进行通信。如果我关闭或终止客户端应用程序，服务器应用程序将获得数千个无用的数据。服务器端的textView充满了这个：Client says: null。如果我关闭客户端两次，服务器将停止StackOverFlowError。如何让代码在应用程序停止时不发送此null值？或者我可以过滤服务器端以获取此数据时什么也不做？客户端：

 public class Client extends Activity {

    private Socket socket;

    private static final int SERVERPORT = 5000;
    private static final String SERVER_IP = "10.0.2.2";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);      

        new Thread(new ClientThread()).start();
    }

    public void onClick(View view) {
        try {
            EditText et = (EditText) findViewById(R.id.EditText01);
            String str = et.getText().toString();
            PrintWriter out = new PrintWriter(new BufferedWriter(
                    new OutputStreamWriter(socket.getOutputStream())),
                    true);
            out.println(str);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    class ClientThread implements Runnable {

        @Override
        public void run() {

            try {
                InetAddress serverAddr = InetAddress.getByName(SERVER_IP);

                socket = new Socket(serverAddr, SERVERPORT);

            } catch (UnknownHostException e1) {
                e1.printStackTrace();
            } catch (IOException e1) {
                e1.printStackTrace();
            }

        }

    }
}

服务器：

public class Server extends Activity {

    private ServerSocket serverSocket;

    Handler updateConversationHandler;

    Thread serverThread = null;

    private TextView text;



    public static final int SERVERPORT = 1599;

    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        text = (TextView) findViewById(R.id.text2);

        updateConversationHandler = new Handler();

        this.serverThread = new Thread(new ServerThread());
        this.serverThread.start();

    }

    @Override
    protected void onStop() {
        super.onStop();
        try {
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    class ServerThread implements Runnable {

        public void run() {
            Socket socket = null;
            try {
                serverSocket = new ServerSocket(SERVERPORT);
            } catch (IOException e) {
                e.printStackTrace();
            }
            while (!Thread.currentThread().isInterrupted()) {

                try {

                    socket = serverSocket.accept();

                    CommunicationThread commThread = new CommunicationThread(socket);
                    new Thread(commThread).start();

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

    class CommunicationThread implements Runnable {

        private Socket clientSocket;

        private BufferedReader input;

        public CommunicationThread(Socket clientSocket) {

            this.clientSocket = clientSocket;

            try {

                this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));

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

        public void run() {


            while (!Thread.currentThread().isInterrupted()) {

                try {

                    String read = input.readLine();

                    updateConversationHandler.post(new updateUIThread(read));

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

    }

    class updateUIThread implements Runnable {
        private String msg;

        public updateUIThread(String str) {
            this.msg = str;
        }

        @Override
        public void run() {
            text.setText(text.getText().toString()+"Client Says: "+ msg + "\n");
        }

    }

}

Answer 1

我认为您应该使用分隔符，告诉服务器您的客户即将死亡。在Android Activity / Fragment的onPause方法中添加该代码字符。然后在您的服务器中，只需获取字符串或字节，并将其与您的分隔符字符串/字符进行比较，并停止服务器侦听连接。

Answer 2

while (!Thread.currentThread().isInterrupted()) {

                try {

                    String read = input.readLine();

                    updateConversationHandler.post(new updateUIThread(read));

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

问题出在这里。您没有检查readLine()的结果为null。如果它返回null，则对等体已关闭连接，您应该这样做，并退出此循环。您也可以摆脱isInterrupted()测试。

此外，如果从套接字读取时有任何IOException其他读取超时，则连接已关闭，您必须关闭套接字并退出循环。

如何阻止Socket在关闭时发送大量无用数据？

2 个答案: