C#抓取网站内容

<form id="form1" runat="server">
    <div id="div_html" runat="server">
    
    </div>
    <input type="button" id="btnok" runat="server" value="获取温度" onserverclick="btnok_ServerClick"/>
        <asp:Button ID="btnNews" runat="server" OnClick="btnNews_Click" Text="新闻" />
        <table>
        <asp:Repeater ID="rptNews" runat="server">
            <ItemTemplate>      
                <tr>
                    <td>ID</td>
                    <td>Name</td>
                    <td>Pic</td>
                </tr>
                <tr>
                    <td><%#Eval("ID") %></td>
                    <td><%#Eval("Name") %></td>
                    <td><%#Eval("Pic")%></td>
                </tr>       
                </ItemTemplate>
        </asp:Repeater>
        </table>
    </form>

 

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text.RegularExpressions;
using System.IO;
using System.Net;
using System.Text;

namespace sqlhelper
{
    public partial class WebForm2 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            
        }

        #region  抓天气

        protected void btnok_ServerClick(object sender, EventArgs e)
        {
            string Htm = _GetHtml(@"http://php.weather.sina.com.cn/search.php?city=北京");

            string pat_city = "<div class=\"City_Data\">" + @"(?:.|\n)*?<h3>(?:[\u4e00-\u9fa5]+)(?:\s+)([\u4e00-\u9fa5]+)</h3>";
            string pat_date = "<div class=\"City_Data\">" + @"(?:.|\n)*?<p>(?:\d+[\u4e00-\u9fa5]+)+?-(?:\d+[\u4e00-\u9fa5]+)&nbsp;([\u4e00-\u9fa5]+)</p>";
            string pat_wea = "<div class=\"Weather_TP\">" + @"[\u4e00-\u9fa5]+\s+(-?\d+℃～-?\d+℃)</div>";

            string str_city = Regex.Match(Htm, pat_city).Groups[1].Value;
            string str_date = Regex.Match(Htm, pat_date).Groups[1].Value;
            string str_wea = Regex.Match(Htm, pat_wea).Groups[1].Value;

            div_html.InnerHtml = str_city + str_date + str_wea;
        } 

        public static string _GetHtml(string Url)
        {

            Stream MyInStream = null;
            string Html = "";
            try
            {
                HttpWebRequest MyRequest = (HttpWebRequest)WebRequest.Create(Url);
                HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();

                MyInStream = MyResponse.GetResponseStream();

                Encoding encode = System.Text.Encoding.Default; //这里编码为:utf-8//System.Text.Encoding.Default;
                StreamReader sr = new StreamReader(MyInStream, encode);

                Char[] read = new Char[256];
                int count = sr.Read(read, 0, 256);
                while (count > 0)
                {
                    String str = new String(read, 0, count);
                    Html += str;
                    count = sr.Read(read, 0, 256);
                }
            }
            catch (Exception)
            {
                Html = "错误";
            }
            finally
            {
                if (MyInStream != null)
                {
                    MyInStream.Close();
                }
            }
            return Html;
        }

        #endregion

        #region  抓新闻

        protected void btnNews_Click(object sender, EventArgs e)
        {
            rptNews.DataSource =GetHtmlCode(@"http://bbs.le8le.com/forumdisplay.php?fid=62", 7);

            //rptNews.DataSource = GetHtmlCode(@"http://news.sina.com.cn/china/", 3);
            rptNews.DataBind();
        }

        DataTable dt = new DataTable();

        private void Setdt()
        {

            dt.Columns.Add("ID");
            dt.Columns.Add("Name");
            dt.Columns.Add("URL");
            dt.Columns.Add("Pic");
        } 

        /// <summary> 
        /// 采集数据 
        /// </summary> 
        /// <param name="Url">需要采集的URL地址</param> 
        /// <param name="i">采集多少条</param> 
        /// <returns>DataTable</returns> 
        public DataTable GetHtmlCode(string Url, int i)
        {
            string strHtml = "";;
            strHtml = GetURlHTML(Url);
            try
            {
                Setdt();
                //关键所在正则表达式，[\\S\\s]*? 匹配所有字符 
                //<span id="thread_2224"><a href="viewthread.php?tid=2224&extra=page%3D1">2008-09赛季前瞻</a></span>所有满足这种条件的数据 
                string TempRegex = "<span id=\"([\\S\\s]*?)\"><a href=\"([\\S\\s]*?)\">([\\S\\s]*?)</a></span>";
                Regex regex = new Regex(TempRegex, RegexOptions.Compiled | RegexOptions.IgnoreCase);




                //string TempRegex = @"<table width=320 cellspacing=0 style='margin:7px 0 7px 0'>(?:.|\n)*?<a\s+href=(.*?)\s+target=_blank>(.*?)</a>(.|\n)*?</table>";
                //string pat_htm = Regex.Match(strHtml, TempRegex).Groups[0].Value; //先把要抓取的一段提出来
                ////一个一个匹配 <a\s+href=(.*?)(?=\s+target=_blank)(.|\n)*?</a>  (?=\s+target=_blank)后面没有>不然不能匹配
                //string pat_href_text = @"<a\s+href=(.*?)\s+target=_blank>(.*?)</a>";
                //Regex regex = new Regex(pat_href_text, RegexOptions.Compiled | RegexOptions.IgnoreCase);


                int x = 1;
                i++;

                for (Match match = regex.Match(strHtml); match.Success; match = match.NextMatch())
                {
                    if (x < i)
                    {
                        DataRow datarow = dt.NewRow();
                        datarow["ID"] = x;
                        //datarow["URL"] = match.Groups[1].Value;
                        //datarow["Name"] = match.Groups[2].Value;
                        datarow["Name"] = match.Groups[3].ToString();
                        datarow["Url"] = GetBBSUrl(Url, match.Groups[2].ToString());
                        datarow["Pic"] = datarow["Url"].ToString();

                        dt.Rows.Add(datarow);
                        dt.AcceptChanges();
                        x++;
                    }
                    else
                    {
                        break;
                    }
                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            return dt;

        }

        /// <summary> 
        /// 获取一条BBS连接的真正外网地址 
        /// </summary> 
        /// <param name="Url">要采集的网址</param> 
        /// <param name="BBSUrl">一条BBS连接</param> 
        /// <returns>一条BBS连接真正地址</returns> 
        private string GetBBSUrl(string Url, string BBSUrl)
        {
            string TempUrl = Url.Substring(0, Url.LastIndexOf("/") + 1);
            return TempUrl + BBSUrl;
        }


        /// <summary> 
        /// 获取URL的HTML 
        /// </summary> 
        /// <param name="Url">URL地址</param> 
        /// <returns>HTML代码</returns> 
        private string GetURlHTML(string Url)
        {
            string strHtml = "";
            try
            {
                StreamReader sr = null;         //用来读取流 
                System.Text.Encoding code = System.Text.Encoding.Default;  //定义编码 

                //构造web请求，发送请求，获取响应 
                WebRequest HttpWebRequest = null;
                WebResponse HttpWebResponse = null;
                HttpWebRequest = WebRequest.Create(Url);
                HttpWebResponse = HttpWebRequest.GetResponse();

                //获得流 
                sr = new StreamReader(HttpWebResponse.GetResponseStream(), code);
                strHtml = sr.ReadToEnd();
                sr.Close();
                //sr.Dispose(); 
                HttpWebResponse.Close();
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            return strHtml;

        }


        /// <summary> 
        /// 获取一条BBS连接内力的图片和图片地址 
        /// </summary> 
        /// <param name="HtmlCode">HtmlCode代码</param> 
        /// <param name="regex1"></param> 
        /// <returns></returns> 
        private string SaveImgToLocal(string URl)
        {
            DataTable dtimg = new DataTable();
            dtimg.Columns.Add("imgpath");

            //string HTML = GetURlHTML(URl);
            string HTML = GetURlHTML(@"http://bbs.le8le.com/viewthread.php?tid=2223&extra=page%3D1");

            string Temp = "<img.*?src=\"(.*?)\".*?/>";//HTML-htm-pat
            //HTML-htm 用(?=exp的方法来确定末尾在那里)
            string Contm = "<div id=\"postmessage_8769\" class=\"t_msgfont\">(.|\\n)*</div>(?=(.|\\n)*?<div id=\"post_rate_div_8769\">)"; 
            Regex regex = new Regex(Contm, RegexOptions.Compiled | RegexOptions.IgnoreCase);
            string htm = regex.Match(HTML).Groups[0].Value;

            string PicUrl = "";
            regex = new Regex(Temp, RegexOptions.Compiled | RegexOptions.IgnoreCase);
            //PicUrl = regex.Match(htm).Groups[1].Value;

            for (Match match = regex.Match(htm); match.Success; match = match.NextMatch())
            {
                DataRow dtimgrow = dtimg.NewRow();
                dtimgrow["imgpath"] = match.Groups[1].Value;

                dtimg.Rows.Add(dtimgrow);
                dtimg.AcceptChanges();
            }

            return PicUrl;
        }

        #endregion




    }
}