HttpWebRequest使用HEAD方法获取远程文件大小

string url = "http://www.mzwu.com/test.apk";
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
request.Method = "HEAD";
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
if (response.StatusCode == HttpStatusCode.OK)
{
    Console.WriteLine(response.ContentLength);
}