响应未进入（android 套接字编程/tcp/ip 套接字编程）

Question

我正在开发一个 Android 应用程序，在该应用程序中，我必须在服务器上发送位置数据并获取工作数据作为响应，所有通信都已建立，但我一直在想一件事我试图从服务器读取响应，但没有任何输出，也没有任何响应，所以请帮助我摆脱困境。下面是我的代码。提前致谢。

   public static class  MyClientTask extends AsyncTask<Void, Void, Void> {
        String dstAddress;
        int dstPort;
        String response = "";
        String s;
        String red;
        String loc;
        String msg;
        Socket socket = null;
        DataOutputStream dataOutputStream = null;
       DataInputStream dataInputStream = null;
       InputStream is=null;
       BufferedReader br=null;
        public MyClientTask(String addr, int port,String msg){
         dstAddress = addr;
         dstPort = port;
         loc=msg;
        }
        @Override
        protected Void doInBackground(Void... arg0) {

            try {
                  socket = new Socket(dstAddress, dstPort);
                  socket.setKeepAlive(true);
                  dataOutputStream = new DataOutputStream(socket.getOutputStream());
                  is=socket.getInputStream();
                 socket.setSoTimeout(60*1000);
                  dataInputStream = new DataInputStream(is);

                  Log.i("socket connect","socket OK");
                  dataOutputStream.writeUTF(loc);
                  while (dataInputStream == null)
                    {
                        ////this part is not working
                        Log.i("DEV", "sleep "+is.available());
                        android.os.SystemClock.sleep(100);
                    }
                  br=new BufferedReader(new InputStreamReader(dataInputStream));
                  String st = null; 
                  while(socket.isConnected()){  
                       st = br.readLine(); 
                       }
                  Log.w("server response", "says Server = " + st);

                  Dbase db2=new Dbase(mcontext);
                   db2.addresponse(new info(st));
                  Log.w("second time server response", "says 2ndTime Server = " + st);
              } catch (UnknownHostException e) {
                  Log.e("at exception", "at thread unknownHost " + e.getMessage());
                  e.printStackTrace();
              } catch (IOException e) {
                  Log.e("io exception", "at thread IO " + e.getMessage());
                  e.printStackTrace();
              }

              finally{
                  Log.i("on finally block", "finally");
                  if (dataOutputStream != null){
                      try {
                          dataOutputStream.close();
                      } catch (IOException e) {
                          Log.e("io eception", "at thread dataoutput IO " + e.getMessage());
                          e.printStackTrace();
                      }
                  }

                  if (dataInputStream != null){
                      try {
                          dataInputStream.close();
                      } catch (IOException e) {
                          Log.e("data input exception", "at thread datainput IO " + e.getMessage());
                          e.printStackTrace();
                      }
                  }
                  if (socket != null){
                      try {
                          Log.i("socket", "socket closed");
                          socket.close();
                      } catch (IOException e) {
                          Log.e("socket exception", "at thread finally IO " + e.getMessage());
                          e.printStackTrace();
                      }
                  }
              }
              return null;
          }

             @Override
             protected void onPreExecute() {
                super.onPreExecute();
                //displayProgressBar("Downloading...");
             }


             @Override
             protected void onPostExecute(Void result) {
                super.onPostExecute(result);
             }
      }

Answer 1

您使用的InputStream.available方法不正确。此方法不会尝试检索数据。实际上，此方法的大多数实现总是 return 0。参见 Inputstream available reference。 我建议您只删除可用的检查并根据需要让 readLine 阻塞。 BufferedReader.ready 也是如此 - 通常这并不表明您在尝试读取时会获得任何数据，因此此调用也没有用。