[转] – 使用 HttpWebRequest 下载任意类型的文件 HttpWebRequest Download Http Url

String url = http://img04.taobaocdn.com/sns_album/i4/T1yAdWXgdGXXb1upjX.jpg;
String fileName
= url.Substring(url.LastIndexOf(/) + 1);
String refer
= url.Substring(0, url.LastIndexOf(/) + 1);
System.Net.HttpWebRequest req
= System.Net.HttpWebRequest.Create(url) as System.Net.HttpWebRequest;
req.AllowAutoRedirect
= true;
req.Referer
= refer;
req.UserAgent
= Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-CN; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13;
System.Net.HttpWebResponse res
= req.GetResponse() as System.Net.HttpWebResponse;
System.IO.Stream stream
= res.GetResponseStream();
byte[] buffer = new byte[32 * 1024];
int bytesProcessed = 0;
System.IO.FileStream fs
= System.IO.File.Create(Server.MapPath(fileName));
int bytesRead;
do
{
  bytesRead
= stream.Read(buffer, 0, buffer.Length);
  fs.Write(buffer,
0, bytesRead);
  bytesProcessed
+= bytesRead;
}
while (bytesRead > 0);
fs.Flush();
fs.Close();
res.Close();

引文来源  使用 HttpWebRequest 下载任意类型的文件 HttpWebRequest Download Http Url