Asp.net 使用正则和网络编程抓取网页数据(实用)

Asp.net 使用正则和网络编程抓取网页数据(实用)

/// <summary>
/// 抓取网页相应内容
/// </summary>
/// <param name="strUrl">采集地址</param>
/// <param name="Begin">开始字符</param>
/// <param name="End">结束字符</param>
/// <returns></returns>
private static String GetContent(String strUrl, String Begin, String End)
{
String result = String.Empty;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(strUrl);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.Default))
{
result = reader.ReadToEnd();

reader.Close();
response.Close();
}

//抓取内容
Match table = Regex.Match(result, "(?<=" + Begin + ")[\\s\\S]*?(?=" + End + ")", RegexOptions.IgnoreCase);
result = NoHTML(table.Value);

return result;
}

///<summary>
///去除HTML标记
///</summary>
///<param   name="NoHTML">包括HTML的源码   </param>
///<returns>已经去除后的文字</returns>
private static string NoHTML(string Htmlstring)
{
//删除脚本
Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "",
RegexOptions.IgnoreCase);
//删除HTML
Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"([\r\n])[\s]+", "",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "\"",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", "   ",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "\xa1",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "\xa2",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "\xa3",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "\xa9",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&#(\d+);", "",
RegexOptions.IgnoreCase);

Htmlstring = Regex.Replace(Htmlstring, ">", "");
Htmlstring = Regex.Replace(Htmlstring, "<", "");
Htmlstring = Regex.Replace(Htmlstring, "\r\n", "");
Htmlstring = Htmlstring.Substring(Htmlstring.IndexOf("\n") + 1);
if (Htmlstring.LastIndexOf("'") >= 0)
Htmlstring = Htmlstring.Substring(Htmlstring.LastIndexOf("'") + 1);
if (Htmlstring.IndexOf("class='tdbk'") >= 0)
Htmlstring = Htmlstring.Substring(Htmlstring.IndexOf("class='tdbk'") + "class='tdbk'".Length);

return Htmlstring;
}