asp.net 抓取網(wǎng)頁源碼三種實(shí)現(xiàn)方法

/// summary>  
 
    /// 用HttpWebRequest取得網(wǎng)頁源碼  
    /// 對于帶BOM的網(wǎng)頁很有效，不管是什么編碼都能正確識別  
    /// /summary>  
    /// param name="url">網(wǎng)頁地址" /param>  
    /// returns>返回網(wǎng)頁源文件/returns>  
    public static string GetHtmlSource2(string url)
    {
      //處理內(nèi)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)"; // 模擬使用IE在瀏覽 http://www.52mvc.com
      request.AllowAutoRedirect = true;//是否允許302
      //request.CookieContainer = new CookieContainer();//cookie容器，
      request.Referer = url; //當(dāng)前頁面的引用
 
 
      HttpWebResponse response = (HttpWebResponse)request.GetResponse();
      Stream stream = response.GetResponseStream();
      StreamReader reader = new StreamReader(stream, Encoding.Default);
      html = reader.ReadToEnd();
      stream.Close();
 
 
      return html;
    }

using System;
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 = null;
      string sRslt = null;
      WebResponse oWebRps = null;
      WebRequest oWebRqst = WebRequest.Create(Url);
      oWebRqst.Timeout = 50000;
      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 sRslt;
    }
 
  }
}

public static string getHtml(string url, params string [] charSets)//url是要訪問的網(wǎng)站地址，charSet是目標(biāo)網(wǎng)頁的編碼，如果傳入的是null或者""，那就自動分析網(wǎng)頁的編碼
  {
    try
    {
      string charSet = null;
      if (charSets.Length == 1) {
        charSet = charSets[0];
      }
      WebClient myWebClient = new WebClient(); //創(chuàng)建WebClient實(shí)例myWebClient
      // 需要注意的：
      //有的網(wǎng)頁可能下不下來，有種種原因比如需要cookie,編碼問題等等
      //這是就要具體問題具體分析比如在頭部加入cookie
      // webclient.Headers.Add("Cookie", cookie);
      //這樣可能需要一些重載方法。根據(jù)需要寫就可以了
 
 
      //獲取或設(shè)置用于對向 Internet 資源的請求進(jìn)行身份驗(yàn)證的網(wǎng)絡(luò)憑據(jù)。
      myWebClient.Credentials = CredentialCache.DefaultCredentials;
      //如果服務(wù)器要驗(yàn)證用戶名,密碼
      //NetworkCredential mycred = new NetworkCredential(struser, strpassword);
      //myWebClient.Credentials = mycred;
      //從資源下載數(shù)據(jù)并返回字節(jié)數(shù)組。（加@是因?yàn)榫W(wǎng)址中間有"/"符號）
      byte[] myDataBuffer = myWebClient.DownloadData(url);
      string strWebData = Encoding.Default.GetString(myDataBuffer);
 
 
      //獲取網(wǎng)頁字符編碼描述信息
      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 ""; }
  }

private string GetStringByUrl(string strUrl) 
{ 
  WebRequest wrt = WebRequest.Create(strUrl); 
  WebResponse wrse = wrt.GetResponse(); 
  Stream strM = wrse.GetResponseStream(); 
  StreamReader SR = new StreamReader(strM,  Encoding.GetEncoding("gb2312")); 
  string strallstrm = SR.ReadToEnd(); 
  return strallstrm; 
} 

private string SaveHTML() 
 {     
string str = RenderPage("Default2.aspx"); 
    Response.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8"); //解決中文亂碼 
    Response.AddHeader("Content-Disposition","attachment;filename=index.html"); //解決中文文件名亂碼   
    Response.AddHeader("Content-length",str.Length.ToString()); 
    Response.Write(str); 
    Response.End(); 
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