正则表达式相关：C# 抓取网页类（获取网页中所有信息）

类的代码：

 using System;
 using System.Data;
 using System.Configuration;
 using System.Net;
 using System.IO;
 using System.Text;
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
 using System.Threading;
 using System.Web;
 using System.Web.UI.MobileControls;
     /// <summary>
     /// 网页类
     /// </summary>
     public class WebPage
     {
         #region 私有成员
         private Uri m_uri;   //url
         private List<Link> m_links;    //此网页上的链接
         private string m_title;        //标题
         private string m_html;         //HTML代码
         private string m_outstr;       //网页可输出的纯文本
         private bool m_good;           //网页是否可用
         private int m_pagesize;       //网页的大小
         private static Dictionary<string, CookieContainer> webcookies = new Dictionary<string, CookieContainer>();//存放所有网页的Cookie  

         #endregion  

         #region 属性  

         /// <summary>
         /// 通过此属性可获得本网页的网址，只读
         /// </summary>
         public string URL
         {
             get
             {
                 return m_uri.AbsoluteUri;
             }
         }  

         /// <summary>
         /// 通过此属性可获得本网页的标题，只读
         /// </summary>
         public string Title
         {
             get
             {
                 if (m_title == "")
                 {
                     Regex reg = new Regex(@"(?m)<title[^>]*>(?<title>(?:\w|\W)*?)</title[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase);
                     Match mc = reg.Match(m_html);
                     if (mc.Success)
                         m_title = mc.Groups["title"].Value.Trim();
                 }
                 return m_title;
             }
         }
         public string M_html
         {
             get
             {
                 if (m_html == null)
                 {
                     m_html = "";
                 }
                 return m_html;
             }
         }
         /// <summary>
         /// 此属性获得本网页的所有链接信息，只读
         /// </summary>
         public List<Link> Links
         {
             get
             {
                 if (m_links.Count == ) getLinks();
                 return m_links;
             }
         }  

         /// <summary>
         /// 此属性返回本网页的全部纯文本信息，只读
         /// </summary>
         public string Context
         {
             get
             {
                 if (m_outstr == "") getContext(Int16.MaxValue);
                 return m_outstr;
             }
         }  

         /// <summary>
         /// 此属性获得本网页的大小
         /// </summary>
         public int PageSize
         {
             get
             {
                 return m_pagesize;
             }
         }
         /// <summary>
         /// 此属性获得本网页的所有站内链接
         /// </summary>
         public List<Link> InsiteLinks
         {
             get
             {
                 return getSpecialLinksByUrl("^http://" + m_uri.Host, Int16.MaxValue);
             }
         }  

         /// <summary>
         /// 此属性表示本网页是否可用
         /// </summary>
         public bool IsGood
         {
             get
             {
                 return m_good;
             }
         }
         /// <summary>
         /// 此属性表示网页的所在的网站
         /// </summary>
         public string Host
         {
             get
             {
                 return m_uri.Host;
             }
         }
         #endregion  

         /// <summary>
         /// 从HTML代码中分析出链接信息
         /// </summary>
         /// <returns>List<Link></returns>
         private List<Link> getLinks()
         {
             if (m_links.Count == )
             {
                 Regex[] regex = new Regex[];
                 regex[] = new Regex(@"<a\shref\s*=""(?<URL>[^""]*).*?>(?<title>[^<]*)</a>", RegexOptions.IgnoreCase | RegexOptions.Singleline);
                 regex[] = new Regex("<[i]*frame[^><]+src=(\"|')?(?<url>([^>\"'\\s)])+)(\"|')?[^>]*>", RegexOptions.IgnoreCase);  

                 for (int i = ; i < ; i++)
                 {
                     Match match = regex[i].Match(m_html);
                     while (match.Success)
                     {
                         try
                         {
                             string url = HttpUtility.UrlDecode(new Uri(m_uri, match.Groups["URL"].Value).AbsoluteUri);  

                             string text = "";
                             if (i == ) text = new Regex("(<[^>]+>)|(\\s)|( )|&|\"", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(match.Groups["text"].Value, "");  

                             Link link = new Link();
                             link.Text = text;
                             link.NavigateUrl = url;  

                             m_links.Add(link);
                         }
                         catch (Exception ex) { Console.WriteLine(ex.Message); };
                         match = match.NextMatch();
                     }
                 }
             }
             return m_links;
         }
         /// <summary>
         /// 此私有方法从一段HTML文本中提取出一定字数的纯文本
         /// </summary>
         /// <param name="instr">HTML代码</param>
         /// <param name="firstN">提取从头数多少个字</param>
         /// <param name="withLink">是否要链接里面的字</param>
         /// <returns>纯文本</returns>
         private string getFirstNchar(string instr, int firstN, bool withLink)
         {
             if (m_outstr == "")
             {
                 m_outstr = instr.Clone() as string;
                 m_outstr = new Regex(@"(?m)<script[^>]*>(\w|\W)*?</script[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");
                 m_outstr = new Regex(@"(?m)<style[^>]*>(\w|\W)*?</style[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");
                 m_outstr = new Regex(@"(?m)<select[^>]*>(\w|\W)*?</select[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");
                 if (!withLink) m_outstr = new Regex(@"(?m)<a[^>]*>(\w|\W)*?</a[^>]*>", RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(m_outstr, "");
                 Regex objReg = new System.Text.RegularExpressions.Regex("(<[^>]+?>)| ", RegexOptions.Multiline | RegexOptions.IgnoreCase);
                 m_outstr = objReg.Replace(m_outstr, "");
                 Regex objReg2 = new System.Text.RegularExpressions.Regex("(\\s)+", RegexOptions.Multiline | RegexOptions.IgnoreCase);
                 m_outstr = objReg2.Replace(m_outstr, " ");  

             }
             return m_outstr.Length > firstN ? m_outstr.Substring(, firstN) : m_outstr;
         }  

         #region 公有文法
         /// <summary>
         /// 此公有方法提取网页中一定字数的纯文本，包括链接文字
         /// </summary>
         /// <param name="firstN">字数</param>
         /// <returns></returns>
         public string getContext(int firstN)
         {
             return getFirstNchar(m_html, firstN, true);
         }  

         /// <summary>
         /// 此公有方法从本网页的链接中提取一定数量的链接，该链接的URL满足某正则式
         /// </summary>
         /// <param name="pattern">正则式</param>
         /// <param name="count">返回的链接的个数</param>
         /// <returns>List<Link></returns>
         public List<Link> getSpecialLinksByUrl(string pattern, int count)
         {
             if (m_links.Count == ) getLinks();
             List<Link> SpecialLinks = new List<Link>();
             List<Link>.Enumerator i;
             i = m_links.GetEnumerator();
             int cnt = ;
             while (i.MoveNext() && cnt < count)
             {
                 if (new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase).Match(i.Current.NavigateUrl).Success)
                 {
                     SpecialLinks.Add(i.Current);
                     cnt++;
                 }
             }
             return SpecialLinks;
         }  

         /// <summary>
         /// 此公有方法从本网页的链接中提取一定数量的链接，该链接的文字满足某正则式
         /// </summary>
         /// <param name="pattern">正则式</param>
         /// <param name="count">返回的链接的个数</param>
         /// <returns>List<Link></returns>
         public List<Link> getSpecialLinksByText(string pattern, int count)
         {
             if (m_links.Count == ) getLinks();
             List<Link> SpecialLinks = new List<Link>();
             List<Link>.Enumerator i;
             i = m_links.GetEnumerator();
             int cnt = ;
             while (i.MoveNext() && cnt < count)
             {
                 if (new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase).Match(i.Current.Text).Success)
                 {
                     SpecialLinks.Add(i.Current);
                     cnt++;
                 }
             }
             return SpecialLinks;
         }  

         /// <summary>
         /// 这公有方法提取本网页的纯文本中满足某正则式的文字  by 何问起
         /// </summary>
         /// <param name="pattern">正则式</param>
         /// <returns>返回文字</returns>
         public string getSpecialWords(string pattern)
         {
             if (m_outstr == "") getContext(Int16.MaxValue);
             Regex regex = new Regex(pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase);
             Match mc = regex.Match(m_outstr);
             if (mc.Success)
                 return mc.Groups[].Value;
             return string.Empty;
         }
         #endregion  

         #region 构造函数  

         private void Init(string _url)
         {
             try
             {
                 m_uri = new Uri(_url);
                 m_links = new List<Link>();
                 m_html = "";
                 m_outstr = "";
                 m_title = "";
                 m_good = true;
                 if (_url.EndsWith(".rar") || _url.EndsWith(".dat") || _url.EndsWith(".msi"))
                 {
                     m_good = false;
                     return;
                 }
                 HttpWebRequest rqst = (HttpWebRequest)WebRequest.Create(m_uri);
                 rqst.AllowAutoRedirect = true;
                 rqst.MaximumAutomaticRedirections = ;
                 rqst.UserAgent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";
                 rqst.KeepAlive = true;
                 rqst.Timeout = ;
                 lock (WebPage.webcookies)
                 {
                     if (WebPage.webcookies.ContainsKey(m_uri.Host))
                         rqst.CookieContainer = WebPage.webcookies[m_uri.Host];
                     else
                     {
                         CookieContainer cc = new CookieContainer();
                         WebPage.webcookies[m_uri.Host] = cc;
                         rqst.CookieContainer = cc;
                     }
                 }
                 HttpWebResponse rsps = (HttpWebResponse)rqst.GetResponse();
                 Stream sm = rsps.GetResponseStream();
                 if (!rsps.ContentType.ToLower().StartsWith("text/") || rsps.ContentLength >  << )
                 {
                     rsps.Close();
                     m_good = false;
                     return;
                 }
                 Encoding cding = System.Text.Encoding.Default;
                 string contenttype = rsps.ContentType.ToLower();
                 int ix = contenttype.IndexOf("charset=");
                 if (ix != -)
                 {
                     try
                     {
                         cding = System.Text.Encoding.GetEncoding(rsps.ContentType.Substring(ix + "charset".Length + ));
                     }
                     catch
                     {
                         cding = Encoding.Default;
                     }  

                     //该处视情况而定 有的需要解码
                     //m_html = HttpUtility.HtmlDecode(new StreamReader(sm, cding).ReadToEnd());
                     m_html = new StreamReader(sm, cding).ReadToEnd();  

                 }
                 else
                 {
                   //该处视情况而定 有的需要解码
                    //m_html = HttpUtility.HtmlDecode(new StreamReader(sm, cding).ReadToEnd());  

                     m_html = new StreamReader(sm, cding).ReadToEnd();
                     Regex regex = new Regex("charset=(?<cding>[^=]+)?\"", RegexOptions.IgnoreCase);
                     string strcding = regex.Match(m_html).Groups["cding"].Value;
                     try
                     {
                         cding = Encoding.GetEncoding(strcding);
                     }
                     catch
                     {
                         cding = Encoding.Default;
                     }
                     byte[] bytes = Encoding.Default.GetBytes(m_html.ToCharArray());
                     m_html = cding.GetString(bytes);
                     if (m_html.Split('?').Length > )
                     {
                         m_html = Encoding.Default.GetString(bytes);
                     }
                 }
                 m_pagesize = m_html.Length;
                 m_uri = rsps.ResponseUri;
                 rsps.Close();
             }
             catch (Exception ex)
             {  

             }
         }
         public WebPage(string _url)
         {
             string uurl = "";
             try
             {
                 uurl = Uri.UnescapeDataString(_url);
                 _url = uurl;
             }
             catch { };
             Init(_url);
         }
         #endregion
     } 

调用：

WebPage webInfo = new WebPage("http://hovertree.net/");  

webInfo.Context;//不包含html标签的所有内容  

webInfo.M_html;//包含html标签的内容  by 何问起

转自：http://hovertree.com/h/bjaf/jhvb7drd.htm

推荐：http://www.cnblogs.com/roucheng/p/3521864.html