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.

本文链接：https://blog.youkuaiyun.com/bulbul2006/article/details/1003672

本文介绍了一种使用ASP.NET实现的简单方法来获取指定URL的网页源代码。通过两种方式实现：利用WebClient类和WebRequest类。这两种方法均可从远程服务器下载网页内容并将其显示在一个文本框中。

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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;
using System.Text.RegularExpressions;
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;
protected System.Web.UI.WebControls.Button GetText;
private string PageUrl = "";

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

Web Form Designer generated code

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();
}

private void GetText_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();
    ContentHtml.Text = Regex.Replace(ContentHtml.Text,"<[^>]*>", "");
    //替换空格
    ContentHtml.Text = Regex.Replace(ContentHtml.Text,"/s+", " ");
}
}
}