asp.net 抓取网页源码三种实现方法

时间:2021-05-28

方法1 比较推荐

/// <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:// 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 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; } }}

方法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 ""; } }

asp.net 获取网页源文件的方法

有时候我们需要获取 网页源文件,所以用以下这个方法很容易完成任务!

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; }

只要传入要下载网页的地址就OK了!
通过这个方法做个源码导出:

private string SaveHTML() { string str = RenderPage("Default2.aspx"); Response.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8"); //解决中文乱码 Response.AddHeader("Content-Disposition","attachment;filename=index.html"); //解决中文文件名乱码 Response.AddHeader("Content-length",str.Length.ToString()); Response.Write(str); Response.End(); }

以上就是asp.net 抓取网页源码的全部代码了,希望对大家有所帮助。

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