C#抓取网页的几种方法
来源:http://blog.csdn.net/jhl52771/article/details/8348443
方法1 
/// <summary> /// 用HttpWebRequest取得网页源码 /// 对于带BOM的网页很有效,不管是什么编码都能正确识别 /// </summary> /// <param name="url">网页地址" </param> /// <returns>返回网页源文件</returns> public static string GetHtmlSource2(string url) { //处理内容 string html = ""; HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); request.Accept = "*/*"; //接受任意文件 request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.1.4322)"; // 模拟使用IE在浏览 http://www.52mvc.com request.AllowAutoRedirect = true;//是否允许302 //request.CookieContainer = new CookieContainer();//cookie容器, request.Referer = url; //当前页面的引用 HttpWebResponse response = (HttpWebResponse)request.GetResponse(); Stream stream = response.GetResponseStream(); StreamReader reader = new StreamReader(stream, Encoding.Default); html = reader.ReadToEnd(); stream.Close(); return html; }
方法2–
using
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Text;
using System.Net;
namespace MySql
{
    public class GetHttpData
    {
        public static string GetHttpData2(string Url)
        {
            string sException =
            string sRslt =
            WebResponse oWebRps =
            WebRequest oWebRqst = WebRequest.Create(Url);
            oWebRqst.Timeout =
            try
            {
                oWebRps = oWebRqst.GetResponse();
            }
            catch (WebException e)
            {
                sException = e.Message.ToString();
            }
            catch (Exception e)
            {
                sException = e.ToString();
            }
            finally
            {
                if (oWebRps != null)
                {
                    StreamReader oStreamRd = new StreamReader(oWebRps.GetResponseStream(), Encoding.GetEncoding(“utf-8”));
                   sRslt = oStreamRd.ReadToEnd();
                    oStreamRd.Close();
                    oWebRps.Close();
                }
           }
            return
        }
    }
}
{–写法3
public static string getHtml(string url, params string [] charSets)//url是要访问的网站地址,charSet是目标网页的编码,如果传入的是null或者"",那就自动分析网页的编码 { try { string charSet = null; if (charSets.Length == 1) { charSet = charSets[0]; } WebClient myWebClient = new WebClient(); //创建WebClient实例myWebClient // 需要注意的: //有的网页可能下不下来,有种种原因比如需要cookie,编码问题等等 //这是就要具体问题具体分析比如在头部加入cookie // webclient.Headers.Add("Cookie", cookie); //这样可能需要一些重载方法。根据需要写就可以了 //获取或设置用于对向 Internet 资源的请求进行身份验证的网络凭据。 myWebClient.Credentials = CredentialCache.DefaultCredentials; //如果服务器要验证用户名,密码 //NetworkCredential mycred = new NetworkCredential(struser, strpassword); //myWebClient.Credentials = mycred; //从资源下载数据并返回字节数组。(加@是因为网址中间有"/"符号) byte[] myDataBuffer = myWebClient.DownloadData(url); string strWebData = Encoding.Default.GetString(myDataBuffer); //获取网页字符编码描述信息 Match charSetMatch = Regex.Match(strWebData, "<meta([^<]*)charset=([^<]*)\"", RegexOptions.IgnoreCase | RegexOptions.Multiline); string webCharSet = charSetMatch.Groups[2].Value; if (charSet == null || charSet == "") charSet = webCharSet; if (charSet != null && charSet != "" && Encoding.GetEncoding(charSet) != Encoding.Default) { strWebData = Encoding.GetEncoding(charSet).GetString(myDataBuffer); } else { strWebData = Encoding.GetEncoding("utf-8").GetString(myDataBuffer); } return strWebData; } catch (Exception e) { return ""; } }