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 程式師世界 >> 編程語言 >> .NET網頁編程 >> C# >> C#基礎知識 >> C#正則表達式抓取網頁信息類

C#正則表達式抓取網頁信息類

編輯:C#基礎知識
(獲取網頁中所有信息)

類的代碼:

 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>  
     /// 網頁類  
     /// </summary>  
     public class WebPage  
     {  
         #region 私有成員  
         private Uri m_uri;   //url  
         private List<Link> m_links;    //此網頁上的鏈接  
         private string m_title;        //標題  
         private string m_html;         //HTML代碼  
         private string m_outstr;       //網頁可輸出的純文本  
         private bool m_good;           //網頁是否可用  
         private int m_pagesize;       //網頁的大小  
         private static Dictionary<string, CookieContainer> webcookies = new Dictionary<string, CookieContainer>();//存放所有網頁的Cookie  
         
         #endregion  
  
         #region 屬性  
   
         /// <summary>  
         /// 通過此屬性可獲得本網頁的網址,只讀  
         /// </summary>  
         public string URL  
         {  
             get  
             {  
                 return m_uri.AbsoluteUri;  
             }  
         }  
   
         /// <summary>  
         /// 通過此屬性可獲得本網頁的標題,只讀  
         /// </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>  
         /// 此屬性獲得本網頁的所有鏈接信息,只讀  
         /// </summary>  
         public List<Link> Links  
         {  
             get  
             {  
                 if (m_links.Count == 0) getLinks();  
                 return m_links;  
             }  
         }  
   
   
         /// <summary>  
         /// 此屬性返回本網頁的全部純文本信息,只讀  
         /// </summary>  
         public string Context  
         {  
             get  
             {  
                 if (m_outstr == "") getContext(Int16.MaxValue);  
                 return m_outstr;  
             }  
         }  
   
         /// <summary>  
         /// 此屬性獲得本網頁的大小  
         /// </summary>  
         public int PageSize  
         {  
             get  
             {  
                 return m_pagesize;  
             }  
         }  
         /// <summary>  
         /// 此屬性獲得本網頁的所有站內鏈接  
         /// </summary>  
         public List<Link> InsiteLinks  
         {  
             get  
             {  
                 return getSpecialLinksByUrl("^http://" + m_uri.Host, Int16.MaxValue);  
             }  
         }  
   
         /// <summary>  
         /// 此屬性表示本網頁是否可用  
         /// </summary>  
         public bool IsGood  
         {  
             get  
             {  
                 return m_good;  
             }  
         }  
         /// <summary>  
         /// 此屬性表示網頁的所在的網站  
         /// </summary>  
         public string Host  
         {  
             get  
             {  
                 return m_uri.Host;  
             }  
         }  
         #endregion  
   
   
         /// <summary>  
         /// 從HTML代碼中分析出鏈接信息  
         /// </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>  
         /// 此私有方法從一段HTML文本中提取出一定字數的純文本  
         /// </summary>  
         /// <param name="instr">HTML代碼</param>  
         /// <param name="firstN">提取從頭數多少個字</param>  
         /// <param name="withLink">是否要鏈接裡面的字</param>  
         /// <returns>純文本</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>  
         /// 此公有方法提取網頁中一定字數的純文本,包括鏈接文字  
         /// </summary>  
         /// <param name="firstN">字數</param>  
         /// <returns></returns>  
         public string getContext(int firstN)  
         {  
             return getFirstNchar(m_html, firstN, true);  
         }  
   
         /// <summary>  
         /// 此公有方法從本網頁的鏈接中提取一定數量的鏈接,該鏈接的URL滿足某正則式  
         /// </summary>  
         /// <param name="pattern">正則式</param>  
         /// <param name="count">返回的鏈接的個數</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>  
         /// 此公有方法從本網頁的鏈接中提取一定數量的鏈接,該鏈接的文字滿足某正則式  
         /// </summary>  
         /// <param name="pattern">正則式</param>  
         /// <param name="count">返回的鏈接的個數</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>  
         /// 這公有方法提取本網頁的純文本中滿足某正則式的文字  by 何問起
         /// </summary>  
         /// <param name="pattern">正則式</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 構造函數  
   
         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;  
                     }  
                      
                     //該處視情況而定 有的需要解碼  
                     //m_html = HttpUtility.HtmlDecode(new StreamReader(sm, cding).ReadToEnd());  
                     m_html = new StreamReader(sm, cding).ReadToEnd();  
                       
                 }  
                 else  
                 {  
                   //該處視情況而定 有的需要解碼  
                    //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  
     } 

調用:

WebPage webInfo = new WebPage("http://hovertree.net/");  
  
webInfo.Context;//不包含html標簽的所有內容  
  
webInfo.M_html;//包含html標簽的內容  by 何問起
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