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

  
  
  
  

   
   
   
   
   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; 
 }