java - HttpRequestRetryHandler 没有被调用

Question

我使用 HttpClient 和 HttpRequestRetryHandler 在连接或套接字超时时重试。因此，我关闭连接并调用 API，期望调用 HttpRequestRetryHandler。但它没有被调用。甚至没有进入方法。

代码:

HttpClient client = new DefaultHttpClient();
client.getParams().setIntParameter(
HttpConnectionParams.CONNECTION_TIMEOUT,
            CONNECTION_TIMEOUT * 1000);
client.getParams().setIntParameter(HttpConnectionParams.SO_TIMEOUT,
            SOCKET_TIMEOUT * 1000);

// Retry handler which handles request retry
HttpRequestRetryHandler requestRetryHandler = new HttpRequestRetryHandler() {

    @Override
    public boolean retryRequest(IOException exception,
                int executionCount, HttpContext context) {

        if ((exception instanceof ConnectTimeoutException || exception instanceof SocketTimeoutException)
                    && executionCount <= MAX_TRIES) {

            Log.d(TAG, "Retrying connection.");
            return true;

        } 

        return false;
    }
};

((AbstractHttpClient) client)
            .setHttpRequestRetryHandler(requestRetryHandler);

但同时我 try catch ConnectTimeoutException ，如下所示，并且执行确实进入 ConnectTimeoutException 的 catch block 。

try {

    // Making API request

} catch (ConnectTimeoutException ce) {

    // Execution enters here
    ce.printStackTrace();
}

我的 avd 在 Android 版本的 jelly bean 上运行。

代码有问题吗？

打印 ConnectTimeoutException 跟踪时的 Logcat:

Answer 1

我遇到了同样的问题，我想分享我的解决方案(对我有用)。

许多常用的 HTTP 服务器被配置为在一段时间不活动后断开持久连接，以节省系统资源，通常不会通知客户端。请参阅HttpClient Connection keep alive strategy

如果服务器断开连接，您的 HttpRequestRetryHandler 将没有机会重试(完成其工作)。

所以我是这样解决的:

1. 实现了自定义连接保持 Activity 策略

   mHttpClient.setKeepAliveStrategy(new ConnectionKeepAliveStrategy() {
       // Honor 'keep-alive' header
       HeaderElementIterator it = new BasicHeaderElementIterator(
           response.headerIterator(HTTP.CONN_KEEP_ALIVE));
       while (it.hasNext()) {
           HeaderElement he = it.nextElement();
           String param = he.getName(); 
           String value = he.getValue();
           if (value != null && param.equalsIgnoreCase("timeout")) {
               try { return Long.parseLong(value) * 1000; } 
               catch(NumberFormatException ignore) {  }
           }
       }
   
       ......
   
       //.Keep Alive for 30 secs
       return 30 * 1000;
     }
   });
   

2. 然后我实现了自定义重试处理程序:

   HttpRequestRetryHandler retryHandler = new HttpRequestRetryHandler() {
   
       public boolean retryRequest(IOException exception, 
                                   int executionCount, 
                                   HttpContext context) {
           // retry a max of 5 times
           if (executionCount >= 5) return false;
   
           if (exception instanceof NoHttpResponseException) {
               // Retry if the server dropped connection on us
               return true;
           }
   
           //.TODO your custom logic...
   
           Boolean b = (Boolean)
               context.getAttribute(ExecutionContext.HTTP_REQ_SENT);
           boolean sent = (b != null && b.booleanValue());   
           if (!sent) {
               // Retry if the request has not been sent fully or
               // if it's OK to retry methods that have been sent
               return true;
           }
   
           // otherwise do not retry
           return false;
       }
   };
   
   mHttpClient.setHttpRequestRetryHandler(retryHandler);