如何釋放HttpURLConnection字節？

我正在開發一個發送大量http請求（HttpURLConnection）的androi應用程序。一切正常，但我認爲我的對象沒有被釋放。我說，因爲當我看MAT（Eclipse Memory Analyzer）時，它說我保留了很多字節[]。我查看MAT上的字節，它們是我在HttpURLConnection方法中收到的字節。以下是我發送http請求的代碼。還有什麼我可以做的發佈我的對象？如何釋放HttpURLConnection字節？

public static String sendHTTPRequest(String requestURL, int timeout) { 
    HttpURLConnection httpconn = null; 
    try { 

     URI uri = new URI(getUTF8Request(requestURL)); 

     httpconn = (HttpURLConnection) uri.toURL().openConnection(); 
     httpconn.setConnectTimeout(timeout); 
     StringBuilder responseStringBuilder = new StringBuilder(); 

     if (httpconn.getResponseCode() == HttpURLConnection.HTTP_OK) { 
      BufferedReader input = new BufferedReader(
        new InputStreamReader(httpconn.getInputStream(), 
          "ISO-8859-1"), 8192); 
      String strLine = null; 
      while ((strLine = input.readLine()) != null) { 
       responseStringBuilder.append(strLine); 
      } 
      input.close(); 
      strLine = null; 
      input = null; 
     } 

     return responseStringBuilder.toString(); 
    } catch (URISyntaxException e) { 
     httpconn = null; 
     return "Failed to request"; 
    } catch (IOException e) { 
     httpconn = null; 
     return "Failed to request"; 
    } finally { 

     requestURL = null; 
     if (httpconn != null) { 
      httpconn.disconnect(); 
      httpconn = null; 
     } 
    } 
}

來源

2013-12-13 user2494863