android - 使用 Android 时，HTTP 响应总是导致 I/O 异常

Question

下面的代码总是给出 I/O 异常，而我在浏览器中检查了它的工作情况，并且我在 Android Manifest 文件中给出了 Internet 权限。我从点击按钮上这样调用

     CheckMetaData cmd = new CheckMetaData();
        cmd.execute(url);
  ---------class def ---  
private class CheckMetaData extends AsyncTask<String,Integer,InputStream> {    
     protected InputStream doInBackground(String... params) {


                    String url=params[0];

                    DefaultHttpClient client = new DefaultHttpClient();

                            HttpGet getRequest = new HttpGet(url);

                            try {

                               HttpResponse getResponse = client.execute(getRequest);
                               final int statusCode = getResponse.getStatusLine().getStatusCode();

                               if (statusCode != HttpStatus.SC_OK) {
                                  Log.w(getClass().getSimpleName(),
                                      "Error " + statusCode + " for URL " + url);
                                  return null;
                               }

                               HttpEntity getResponseEntity = getResponse.getEntity();
                                   return getResponseEntity.getContent();

                            }
                            catch (IOException e) {
                               getRequest.abort();
                               Log.w(getClass().getSimpleName(), "Error for URL " + url, e);

                            }        
                            return null; 
            }