readUTF() 导致 Android 应用程序挂起

Question

我正在尝试在此链接上编译代码。

代码不起作用，因为它挂在这条线上：

textIn.setText(dataInputStream.readUTF());

出于某种原因，它没有挂断，writeUTF()而是挂断了readUTF()。

任何人都可以指出我正确的方向吗？

这是我的代码：

public Socket socket = null;
public DataOutputStream dataOutputStream = null;
public DataInputStream dataInputStream = null;
public Thread readjsonthrd = new Thread(new ReadJSONThread());

private final static String LOG_TAG = AndroidClient.class.getSimpleName();
private final Handler handler = new Handler();

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

    Log.e(LOG_TAG, "Before OnCreate() Try");
    try {
        Log.e(LOG_TAG, "In OnCreate() Try");
        socket = new Socket("23.23.175.213", 9000);
        Log.e(LOG_TAG, "Created Socket");
        dataOutputStream = new DataOutputStream(socket.getOutputStream());
        Log.e(LOG_TAG, "Created DataOutputStream");
        dataInputStream = new DataInputStream(socket.getInputStream());
        Log.e(LOG_TAG, "Created DataInputStream");

        Profile p = new Profile();
        Log.e(LOG_TAG, "Created Profile Instance");

        //Gets the local profile via JSON and converts into Profile type
        Gson gson = new Gson();
        Log.e(LOG_TAG, "Created Gson Instance");
        p = gson.fromJson(p.getProfileJSONStr(), Profile.class);
        Log.e(LOG_TAG, "Converted Profile to JSON");

        //Gson gson = new Gson();
        Log.e(LOG_TAG, "Before: outputJSON = gson.toJson(p);");
        outputJSON = gson.toJson(p);
        Log.e(LOG_TAG, "Created outputJSON");

        dataOutputStream.writeUTF(outputJSON); //OUTPUT OF JSON FROM LOCAL PROFILE BEING SENT TO THE SERVER
        dataOutputStream.flush();
        Log.e(LOG_TAG, "Created dataOutputStream");
    } catch (UnknownHostException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    Log.e(LOG_TAG, "Before initEventHandlers");
    initEventHandlers();
    Log.e(LOG_TAG, "Create Thread");
    Thread serverthrd = new Thread(new ServerThread());

    Log.e(LOG_TAG, "Start Thread");
    serverthrd.start();
    Log.e(LOG_TAG, "Started Thread");
}

public class ServerThread implements Runnable { 
    @Override
    public void run() {
        // TODO Auto-generated method stub
    //Socket socket = null;
    //DataOutputStream dataOutputStream = null;
    //DataInputStream dataInputStream = null;
        Log.e(LOG_TAG, "Before Server Try Statement");
    try {
        Log.e(LOG_TAG, "In Server Try Statement");
        //socket = new Socket("23.23.175.213", 1337);

        //dataOutputStream = new DataOutputStream(socket.getOutputStream());
        //dataInputStream = new DataInputStream(socket.getInputStream());
        /*Profile p = null;

        //Gets the local profile via JSON and converts into Profile type
        Gson gson = new Gson();
        p = gson.fromJson(p.getProfileJSONStr(), Profile.class);

        //Gson gson = new Gson();
        outputJSON = gson.toJson(p);
        dataOutputStream.writeUTF(outputJSON); //OUTPUT OF JSON FROM LOCAL PROFILE BEING SENT TO THE SERVER
        */
        //dataOutputStream.writeUTF(textOut.getText().toString());  //OUTPUT JSON GOES HERE
        //textIn.setText(dataInputStream.readUTF());


        Log.e(LOG_TAG, "Start Thread");
        readjsonthrd.start();
        Log.e(LOG_TAG, "Started Thread");
        /*Log.e(LOG_TAG, "Before inputJSON String");
        inputJSON = dataInputStream.readUTF();

        //Convert 
        Log.e(LOG_TAG, "After inputJSON String");
        Log.e(LOG_TAG, "InputJSON:" + inputJSON);*/

        //textIn.setText(dataInputStream.readUTF());  //GET JSON COMING FROM SERVER HERE
        refreshViewModels();
    } /*catch (UnknownHostException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }*/
    finally{
        if (socket != null){
            try {
                socket.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        if (dataOutputStream != null){
            try {
                dataOutputStream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        if (dataInputStream != null){
            try {
                dataInputStream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }


    }
}

public class ReadJSONThread implements Runnable { 
    @Override
    public void run() {
        // TODO Auto-generated method stub
    //Socket socket = null;
    //DataOutputStream dataOutputStream = null;
    //DataInputStream dataInputStream = null;
        Log.e(LOG_TAG, "Before Read JSON Try Statement");
        try {
            Log.e(LOG_TAG, "Before inputJSON String");
            inputJSON = dataInputStream.readUTF();

            //Convert 
            Log.e(LOG_TAG, "After inputJSON String");
        }
        catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Answer 1

我在与一个 gov API 集成时遇到了一些类似的问题，我使用的是 readUTF() writeUTF()，并且每次都卡在 readUTF() 没有任何响应。

我发现服务器在 c 中，并且期望以 * 结尾或请求字符串，响应也以 * 结尾。

我解决了这个问题，通过直接写入套接字的输入/输出流，并在遇到 ** 时终止读取。

        Socket client = new Socket(serverIp, port);
        OutputStream out = client.getOutputStream();
        InputStream in = client.getInputStream();

        String test = "REQUEST-STRING**";
        out.write(test.getBytes());
        out.flush();

        int c;
        while ((c=in.read())!=-1) {
            if (isEndOfResponse(c)) {
                break;
            }
            System.out.print((char)c);
        }
        client.close();