using System;using System.Xml;using System.Text;using System.Net;using System.IO;using System.Collections;using System.Text.RegularExpressions;public class App{public static void Main(){　string strCode;ArrayList alLinks;Console.Write("请输入一个网页地址："); string strURL = Console.ReadLine();if(strURL.Substring(0,7) != @"http://"){strURL = @"http://" + strURL;}Console.WriteLine("正在获取页面代码，请稍侯..."); strCode = GetPageSource(strURL);Console.WriteLine("正在提取超链接，请稍侯..."); alLinks = GetHyperLinks(strCode);Console.WriteLine("正在写入文件，请稍侯..."); WriteToXml(strURL,alLinks);}// 获取指定网页的HTML代码static string GetPageSource(string URL){Uri uri =new Uri(URL);HttpWebRequest hwReq = (HttpWebRequest)WebRequest.Create(uri);HttpWebResponse hwRes = (HttpWebResponse)hwReq.GetResponse();hwReq.Method = "Get";hwReq.KeepAlive = false;StreamReader reader = new StreamReader(hwRes.GetResponseStream(),System.Text.Encoding.GetEncoding("GB2312"));return reader.ReadToEnd();}// 提取HTML代码中的网址static ArrayList GetHyperLinks(string htmlCode){ArrayList al = new ArrayList();string strRegex = @"http://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?";Regex r = new Regex(strRegex,RegexOptions.IgnoreCase);MatchCollection m = r.Matches(htmlCode);for(int i=0; i<=m.Count-1; i++){bool rep = false;string strNew = m[i].ToString();// 过滤重复的URLforeach(string str in al){if(strNew==str){rep =true;break;}　 }if(!rep) al.Add(strNew);}al.Sort();return al;}// 把网址写入xml文件static void WriteToXml(string strURL, ArrayList alHyperLinks){XmlTextWriter writer = new XmlTextWriter("HyperLinks.xml",Encoding.UTF8); writer.Formatting = Formatting.Indented;writer.WriteStartDocument(false);writer.WriteDocType("HyperLinks", null, "urls.dtd", null);writer.WriteComment("提取自" + strURL + "的超链接"); writer.WriteStartElement("HyperLinks");writer.WriteStartElement("HyperLinks", null);writer.WriteAttributeString("DateTime",DateTime.Now.ToString());foreach(string str in alHyperLinks){string title = GetDomain(str);string body = str;writer.WriteElementString(title,null,body);}writer.WriteEndElement();writer.WriteEndElement();writer.Flush();writer.Close();}

      // 获取网址的域名后缀static string GetDomain(string strURL){string retVal;string strRegex = @"(\.com/|\.net/|\.cn/|\.org/|\.gov/)";Regex r = new Regex(strRegex,RegexOptions.IgnoreCase); Match m = r.Match(strURL);retVal = m.ToString();strRegex = @"\.|/$";retVal = Regex.Replace(retVal, strRegex, "").ToString();if(retVal == "")retVal = "other";return retVal;}}