ASP.NET使用HttpWebRequest读取远程网页源代码

public string GetPage(string url){  HttpWebRequest request = null;  HttpWebResponse response = null;  StreamReader reader = null;  try  {    request = (HttpWebRequest)WebRequest.Create(url);    request.Timeout = 20000;    request.AllowAutoRedirect = false;    response = (HttpWebResponse)request.GetResponse();    if (response.StatusCode == HttpStatusCode.OK && response.ContentLength < 1024 * 1024)    {      reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.Default);      string html = reader.ReadToEnd();      return html;    }  }  catch  {  }  finally  {    if (response != null)    {      response.Close();      response = null;    }    if (reader != null)      reader.Close();    if (request != null)      request = null;  }  return string.Empty;}