SocketTimeoutException等待但不被抛出？

Question

我正在写一个接收服务器数据的Android应用程序。理论上可能没有互联网连接，所以我尝试通过捕获SocketTimeoutException来显示错误消息，重试屏幕或其他内容来捕获此案例。不幸的是，这个异常不会被抛出。至少它不会跳入catch子句。我究竟做错了什么？

public class HttpConnector { 

    private String urlString; 
    private int connectionTimeout = 5000; //milliseconds 

    public HttpConnector(String urlString) { 
     this.urlString = urlString; 
    } 

    public String receiveData() throws PolizeiwarnungException { 
     URL url = null; 
     HttpURLConnection urlConnection = null; 
     StringBuffer b = new StringBuffer(); 

     try { 
      url = new URL(urlString); 
      urlConnection = (HttpURLConnection) url.openConnection(); 
      urlConnection.setReadTimeout(connectionTimeout); 
      BufferedReader reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream())); //Here it gets stuck if there is no connection to the server 

      String str; 
      while ((str = reader.readLine()) != null) { 
       b.append(str + "\n"); 
      } 
     } 
     catch (SocketTimeoutException e) { 
      //TODO 
      e.printStackTrace(); 
     } 
     catch (IOException e) { 
      throw new PolizeiwarnungException(e); 
     } 
     finally { 
      if (urlConnection != null) { 
       urlConnection.disconnect(); 
      } 
     } 

     return b.toString(); 
    } 

    public void sendData(String data) { 
     //TODO 
    } 
} 

Answer 1

您还需要设置连接超时。 Please see this documentation.

由于终点不存在，所以没有设置连接超时，连接永远不会超时。

setConnectTimeout（INT超时）设置建立由 此URLConnection实例指出了资源的连接毫秒 的超时值。