与 AIS 转发器的 Android 套接字连接引发 IOException

Posted 2023-03-11

【中文标题】与 AIS 转发器的 Android 套接字连接引发 IOException

【英文标题】：Android Socket Connection with AIS Transponder throws IOException

【发布时间】：2018-08-20 15:10:20

【问题描述】：

我正在尝试通过创建与 AIS 转发器的 TCP 连接来通过 WiFi 读取 android 设备上的 AIS 串行数据。我正在使用 EM-Trak B360 AIS 转发器并使用以下代码在 android 设备上创建一个套接字：

public class Client extends AsyncTask<Void, Void, Void> 

  String dstAddress;
  int dstPort;
  String response = "";
  TextView textResponse;

  Client(String addr, int port, TextView textResponse) 
    dstAddress = addr;
    dstPort = port;
    this.textResponse = textResponse;
  

  @Override
  protected Void doInBackground(Void... arg0) 

    Socket socket = null;

    try 
      socket = new Socket(dstAddress, dstPort);

      ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(1024);
      byte[] buffer = new byte[1024];

      int bytesRead;
      InputStream inputStream = socket.getInputStream();

      /*
       * notice: inputStream.read() will block if no data return
       */
      while ((bytesRead = inputStream.read(buffer)) != -1) 
        byteArrayOutputStream.write(buffer, 0, bytesRead);
        response += byteArrayOutputStream.toString("UTF-8");
      

     catch (UnknownHostException e) 
      e.printStackTrace();
      response = "UnknownHostException: " + e.toString();
     catch (IOException e) 
      e.printStackTrace();
      response = "IOException: " + e.toString();
     finally 
      if (socket != null) 
        try 
          socket.close();
         catch (IOException e) 
          e.printStackTrace();
        
      
    
    return response;
  

  @Override
  protected void onPostExecute(Void result) 
    textResponse.setText(response);
    super.onPostExecute(result);
  

上面的代码通过创建移动热点来实现移动到移动的连接。但是，当连接 AIS 转发器的 Wifi 网络时，它会抛出 I/O 异常：软件导致连接中止。

08-20 17:04:39.089 13505-13534/com.hfad.slave W/System.err: java.net.SocketException: Software caused connection abort
08-20 17:04:39.090 13505-13534/com.hfad.slave W/System.err:
  at java.net.PlainSocketImpl.socketConnect(Native Method)
  at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:334)
  at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:196)
  at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:178)
  at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:356)
  at java.net.Socket.connect(Socket.java:586)
  at java.net.Socket.connect(Socket.java:535)
  at java.net.Socket.<init>(Socket.java:427)
  at java.net.Socket.<init>(Socket.java:210)
  at com.hfad.slave.Client.doInBackground(Client.java:47)
  at com.hfad.slave.Client.doInBackground(Client.java:16)
  at android.os.AsyncTask$2.call(AsyncTask.java:304)
  at java.util.concurrent.FutureTask.run(FutureTask.java:237)
  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
  at java.lang.Thread.run(Thread.java:762)

【问题讨论】：

response += byteArrayOutputStream.toString("UTF-8");。你应该把它放在while循环之后。

The above code works for mobile-to-mobile connection by creating a mobile hotspot. ???

@greenapps 代码在创建套接字时抛出异常

@greenapps 我的意思是在任何其他 Wifi 网络上运行代码时，上述代码都有效。仅当 android 设备连接到 AIS 转发器的 Wifi 网络时才会中断。

【参考方案1】：

我找到了问题的解决方案。我使用了 Apache Commons 的 telnetclient 库。 https://commons.apache.org/proper/commons-net/apidocs/org/apache/commons/net/telnet/TelnetClient.html

现在我可以与 AIS 转发器通信了。

谢谢！！