问HttpURLConnection: getResponseMessage()、getInputStream()和getContent()之间的区别

EN

private static String getResponse (HttpURLConnection connection) throws Exception
{
   String responseString = null;
   int responseCode = connection.getResponseCode();
   String responseMessage = connection.getResponseMessage();
   Log.debug("%s - Response code is \"%s\" with message \"%s\"",
          methodName, responseCode, responseMessage);
   String line = null;
   if (responseCode == HttpURLConnection.HTTP_OK) {
       BufferedReader bufferedReader = null;
       try {
           InputStream inputStream = connection.getInputStream();
           if (inputStream != null) {
               bufferedReader = Util.bufferedReader(
                   inputStream, Util.Encod.UTF8);
               StringBuilder response = new StringBuilder();
               while ((line = bufferedReader.readLine()) != null) {
                   response.append(line);
                   response.append(Util.getNewLine());
               }
               responseString = response.toString();
           }
       }
       finally {
           if (bufferedReader != null) {
               bufferedReader.close();
           }
       }
       Log.signature.debug(
           "%s - Received following JSON response : %s",
           methodName,
           responseString);
   }
   return responseString;
} 

String responseMessage = connection.getResponseMessage()

Class URLConnection 
   public Object getContent() throws IOException 
   public Object getContent(Class[] classes) throws IOException