httpConnection.getContentLength（）的替代？

Question

我调用以下函数来获取要下载的文件总大小：

private Uri askForFileSizeFromURL(URL url, String fileName) {
    try {
        URLConnection conn = url.openConnection();
        HttpURLConnection httpConnection = conn instanceof HttpURLConnection ? (HttpURLConnection ) conn  : null;
        int responseCode = httpConnection.getResponseCode();

        if (responseCode == HttpURLConnection.HTTP_OK){

            bytesToDownload += httpConnection.getContentLength();

            return null;
        }
    }
    catch(ConnectException e) {
        Log.d("2ndGuide", "ConnectException." + e);
        downloadAborted = true;
        return null;
    }
    catch(IOException e)
    {
        Log.d("2ndGuide", "IO Exception." + e);
    }
    return null;
}

我调用此功能31次，需要超过23次。没有这个调用，循环需要320ms。所以问题来自这段代码。

是否有更快的方法从Internet上的远程服务器获取文件大小？

此致 阿兰