HttpWebRequest获取网页源代码时自动识别网页编码

HttpWebRequest获取网页源代码时自动识别网页编码，通过读取页面中的charset和读取http头中的编码信息获取页面的编码，基本可以正确获取网页编码

 

  
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  static
   
  string
   GetEncoding(
  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
  ) 
 { 

  if
   (response.ContentEncoding 
  !=
   
  null
   
  &&
   response.ContentEncoding.Equals(
  "
  gzip
  "
  , StringComparison.InvariantCultureIgnoreCase)) 
 reader 
  =
   
  new
   StreamReader(
  new
   GZipStream(response.GetResponseStream(), CompressionMode.Decompress)); 

  else
   
 reader 
  =
   
  new
   StreamReader(response.GetResponseStream(), Encoding.ASCII); 


  string
   html 
  =
   reader.ReadToEnd(); 

 Regex reg_charset 
  =
   
  new
   Regex(
  @"
  charset/b/s*=/s*(?<charset>[^""]*)
  "
  ); 

  if
   (reg_charset.IsMatch(html)) 
 { 

  return
   reg_charset.Match(html).Groups[
  "
  charset
  "
  ].Value; 
 } 

  else
   
  if
   (response.CharacterSet 
  !=
   
  string
  .Empty) 
 { 

  return
   response.CharacterSet; 
 } 

  else
   

  return
   Encoding.Default.BodyName; 
 } 
 } 

  catch
   
 { 
 } 

  finally
   
 { 


  if
   (response 
  !=
   
  null
  ) 
 { 
 response.Close(); 
 response 
  =
   
  null
  ; 
 } 

  if
   (reader 
  !=
   
  null
  ) 
 reader.Close(); 


  if
   (request 
  !=
   
  null
  ) 
 request 
  =
   
  null
  ; 

 } 


  return
   Encoding.Default.BodyName; 
 } 


  ///
   
  <summary>
   

  ///
   获取源代码 

  ///
   
  </summary>
   

  ///
   
  <param name="url"></param>
   

  ///
   
  <returns></returns>
   

   
  static
   
  string
   GetHtml(
  string
   url, Encoding encoding) 
 { 
 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
  ) 
 { 

  if
   (response.ContentEncoding 
  !=
   
  null
   
  &&
   response.ContentEncoding.Equals(
  "
  gzip
  "
  , StringComparison.InvariantCultureIgnoreCase)) 
 reader 
  =
   
  new
   StreamReader(
  new
   GZipStream(response.GetResponseStream(), CompressionMode.Decompress), encoding); 

  else
   
 reader 
  =
   
  new
   StreamReader(response.GetResponseStream(), encoding); 

  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; 
 }