利用WebClient和WebRequest类获得网页源代码

作者：孟宪会

     利用.net框架提供的 WebClient类和 WebRequest类,我们可以很轻易地得到给定URL地址的源代码,很简单,以下是C#的完整的例子.


  查看例子


  GetPageHtml.ASPx


  <%@ Page language="c#" validateRequest = "false" Codebehind="GetPageHtml.aspx.cs"
  AutoEventWireup="false" Inherits="eMeng.Exam.GetPageHtml" %>
  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
  <HTML>
  <HEAD>
  <title>得到网页源代码</title>
  <meta name="GENERATOR" Content="Microsoft Visual Studio 7.0">
  <meta name="CODE_LANGUAGE" Content="C#">
  <meta name="vs_defaultClientScript" content="JavaScript">
  <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
  </HEAD>
  <body MS_POSITIONING="GridLayout">
  <form id="aspNetBuffer" method="post" runat="server">
  <div align="center" style="FONT-WEIGHT: bold">得到任意网页源代码</div>
  <asp:TextBox id="UrlText" runat="server" Width="400px">http://dotnet.aspx.cc/content.aspx
  </asp:TextBox>
  <asp:Button id="WebClientButton" Runat="server" Text="用WebClient得到"></asp:Button>
  <asp:Button id="WebRequestButton" runat="server" Text="用WebRequest得到"></asp:Button>
  <br>
  <asp:TextBox id="ContentHtml" runat="server" Width="100%" Height="360px" TextMode="MultiLine">
  </asp:TextBox>
  </form>
  </body>
  </HTML>


  GetPageHtml.aspx.cs


  using System;
  using System.Collections;
  using System.ComponentModel;
  using System.Data;
  using System.Drawing;
  using System.Web;
  using System.Web.SessionState;
  using System.Web.UI;
  using System.Web.UI.WebControls;
  using System.Web.UI.HtmlControls;
  using System.IO;
  using System.Net;
  using System.Text;


  namespace eMeng.Exam
  {
  /// <summary>
  /// GetPageHtml 的摘要说明。
  /// </summary>
  public class GetPageHtml : System.Web.UI.Page
  {
  protected System.Web.UI.WebControls.Button WebClientButton;
  protected System.Web.UI.WebControls.Button WebRequestButton;
  protected System.Web.UI.WebControls.TextBox ContentHtml;
  protected System.Web.UI.WebControls.TextBox UrlText;
  private string PageUrl = "";

  private void Page_Load(object sender, System.EventArgs e)
  {}


  #region Web Form Designer generated code
  override protected void OnInit(EventArgs e)
  {
  InitializeComponent();
  base.OnInit(e);
  }


  /// <summary>
  /// 设计器支持所需的方法 - 不要使用代码编辑器修改
  /// 此方法的内容。
  /// </summary>
  private void InitializeComponent()
  {
  this.WebClientButton.Click += new System.EventHandler(this.WebClientButton_Click);
  this.WebRequestButton.Click += new System.EventHandler(this.WebRequestButton_Click);
  this.Load += new System.EventHandler(this.Page_Load);
  }
  #endregion

  private void WebClientButton_Click(object sender, System.EventArgs e)
  {
  PageUrl = UrlText.Text;
  WebClient wc = new WebClient();
  wc.Credentials = CredentialCache.DefaultCredentials;


  ///方法一：
  Byte[] pageData = wc.DownloadData(PageUrl);
  ContentHtml.Text = Encoding.Default.GetString(pageData);


  /// 方法二：
  /// ***************代码开始**********
  /// Stream resStream = wc.OpenRead(PageUrl);
  /// StreamReader sr = new StreamReader(resStream,System.Text.Encoding.Default);
  /// ContentHtml.Text = sr.ReadToEnd();
  /// resStream.Close();
  /// **************代码结束********
  ///
  wc.Dispose();
  }


  private void WebRequestButton_Click(object sender, System.EventArgs e)
  {
  PageUrl = UrlText.Text;
  WebRequest request = WebRequest.Create(PageUrl);
  WebResponse response = request.GetResponse();
  Stream resStream = response.GetResponseStream();
  StreamReader sr = new StreamReader(resStream, System.Text.Encoding.Default);
  ContentHtml.Text = sr.ReadToEnd();
  resStream.Close();
  sr.Close();
  }
  }
  }

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