Question

我尝试为应用程序编写一个简单的服务器，用户可以使用telnet将数据写入IP和端口。它运作得很好，它可以显示

问题是，当用户关闭telnet窗口（PC中的CMD窗口，用户连接到应用程序的位置）时，应用程序将停止。

有没有办法防止这种行为？这是我的代码：

//Defined in Activity class 
//Sockets, servers, clients and stuff    
public java.net.ServerSocket MyServerSocket;
public String IpAddress = "";
public int Port = 12345;
public Handler UpdateConversationHandler;
public Thread ServerThread = null;

Activity类中的嵌套类：

class ServerThread implements Runnable{

    public final String IpAddress;
    public final int Port;

    public ServerThread(String ipAddress, int port)
    {
        IpAddress = ipAddress;
        Port = port;
    }

    public void run() {
        Socket socket = null;

        try{
            MyServerSocket = new ServerSocket(Port);
        } catch (IOException e) {
            e.printStackTrace();
        }

        while(!Thread.currentThread().isInterrupted()){
            try{
                socket = MyServerSocket.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() {
        _textview_info.setText("Client Says: "+ msg );

    }
}

我也有onStop方法的代码，但它没有帮助！

@Override
protected void onStop() {
    super.onStop();

    //Closing server socket
    try
    {
        MyServerSocket.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

这是onCreate方法，服务器启动：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    _context = this;

    //Prepare spinners
    _preferences = getSharedPreferences("org.pervasivesystems.nexusmosaic", MODE_PRIVATE);
    _preferencesEditor = _preferences.edit();
    _spinner_videos = (Spinner) findViewById(R.id.spinner_select_video);
    _spinner_ids = (Spinner) findViewById(R.id.spinner_select_id);
    populateSpinners();

    //Prepare server
    IpAddress = getIpAddress();
    TextView tvIpAddress = (TextView) findViewById(R.id.textview_ip_address_value);
    tvIpAddress.setText(IpAddress);
    _textview_info = (TextView) findViewById(R.id.textview_information);
    UpdateConversationHandler = new Handler();
    ServerThread = new Thread(new ServerThread(IpAddress, Port));
    this.ServerThread.start();
}

更新

当我启动应用程序时，甚至在使用telnet从PC连接到应用程序之前，我会在LOGCAT中继续收到以下消息：

11-14 15:45:32.460    W/System.err? at java.lang.Thread.run(Thread.java:856)
11-14 15:45:32.460    W/System.err? java.net.SocketException: Socket is closed
11-14 15:45:32.460    W/System.err? at java.net.ServerSocket.checkOpen(ServerSocket.java:362)
11-14 15:45:32.460     W/System.err? at java.net.ServerSocket.accept(ServerSocket.java:120)
11-14 15:45:32.460    W/System.err? at .MainActivity$ServerThread.run(MainActivity.java:233)

第233行引用此代码：

    while(!Thread.currentThread().isInterrupted()){
        try{
            socket = MyServerSocket.accept(); //LINE 233
            CommunicationThread commThread = new CommunicationThread(socket);
            new Thread(commThread).start();
        } catch (IOException e) {
            e.printStackTrace();
        }

我还发现从PC关闭telnet窗口后，UpdateUiThread一直在运行。

Answer 1

可能发生的事情是您的通信线程注意到已终止的连接并退出。这就是你写它的方式。我不确定你想要它做什么......

如果你想在终止连接后做一些事情，只需在

之后加上一些代码

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

等待线程完成，然后执行您想要的操作。

有时它会帮助我在线程代码中添加一些系统输出来获取事情何时触发/结束的句柄。它会有所帮助，相信我。

Answer 2

试试这个

do{
    if(!Thread.currentThread().isInterrupted()){
        try{

            socket = MyServerSocket.accept();

            if(socket!=null && socket.isConnected()){
                CommunicationThread commThread = new CommunicationThread(socket);
                new Thread(commThread).start();
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
  }while(socket!=null && socket.isConnected());

Android应用程序在关闭PC中的telnet窗口后停止响应

2 个答案: