C#基于正则表达式实现获取网页中所有信息的网页抓取类实例

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 == 0) 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 == 0)      {        Regex[] regex = new Regex[2];        regex[0] = new Regex(@"<a/shref/s*=""(?<URL>[^""]*).*?>(?<title>[^<]*)</a>", RegexOptions.IgnoreCase | RegexOptions.Singleline);        regex[1] = new Regex("<[i]*frame[^><]+src=(/"|')?(?<url>([^>/"'//s)])+)(/"|')?[^>]*>", RegexOptions.IgnoreCase);        for (int i = 0; i < 2; 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 == 0) 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(0, 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 == 0) getLinks();      List<Link> SpecialLinks = new List<Link>();      List<Link>.Enumerator i;      i = m_links.GetEnumerator();      int cnt = 0;      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 == 0) getLinks();      List<Link> SpecialLinks = new List<Link>();      List<Link>.Enumerator i;      i = m_links.GetEnumerator();      int cnt = 0;      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[1].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 = 3;        rqst.UserAgent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";        rqst.KeepAlive = true;        rqst.Timeout = 10000;        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 > 1 << 22)        {          rsps.Close();          m_good = false;          return;        }        Encoding cding = System.Text.Encoding.Default;        string contenttype = rsps.ContentType.ToLower();        int ix = contenttype.IndexOf("charset=");        if (ix != -1)        {          try          {            cding = System.Text.Encoding.GetEncoding(rsps.ContentType.Substring(ix + "charset".Length + 1));          }          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 > 100)          {            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}

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