asp.net HttpWebRequest自動識別網(wǎng)頁編碼

更新時間：2008年09月10日 01:04:55 作者：

HttpWebRequest獲取網(wǎng)頁源代碼時自動識別網(wǎng)頁編碼，通過讀取頁面中的charset和讀取http頭中的編碼信息獲取頁面的編碼，基本可以正確獲取網(wǎng)頁編碼

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> 
/// 獲取源代碼 
/// </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; 
}