通用辅助类 下面是我编写的一个辅助类，在这个类中采用了HttpWebRequest中发送GET/HTTP/HTTPS请求，因为有的时候需要获取认证信息（如Cookie），所以返回的是HttpWebResponse对象，有了返回的HttpWebResponse实例，可以获取登录过程中返回的会话信息，也可以获取响应流。 代码如下： using System;  using System.Collections.Generic;  using System.Linq;  using System.Text;  using System.Net.Security;  using System.Security.Cryptography.X509Certificates;  using System.DirectoryServices.Protocols;  using System.ServiceModel.Security;  using System.Net;  using System.IO;  using System.IO.Compression;  using System.Text.RegularExpressions;  /*     * 作者：周公(zhoufoxcn)     * 日期：2011-05-08     * 原文出处：http://blog.csdn.net/zhoufoxcn 或http://zhoufoxcn.blog.51cto.com     * 版权说明：本文可以在保留原文出处的情况下使用于非商业用途，周公对此不作任何担保或承诺。     * */ namespace BaiduCang  {      /// <summary>      /// 有关HTTP请求的辅助类      /// </summary>      public class HttpWebResponseUtility      {          private static readonly string DefaultUserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";          /// <summary>          /// 创建GET方式的HTTP请求          /// </summary>          /// <param name="url">请求的URL</param>          /// <param name="timeout">请求的超时时间</param>          /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>          /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>          /// <returns></returns>          public static HttpWebResponse CreateGetHttpResponse(string url,int? timeout, string userAgent,CookieCollection cookies)          {              if (string.IsNullOrEmpty(url))              {                  throw new ArgumentNullException("url");              }              HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;              request.Method = "GET";              request.UserAgent = DefaultUserAgent;              if (!string.IsNullOrEmpty(userAgent))              {                  request.UserAgent = userAgent;              }              if (timeout.HasValue)              {                  request.Timeout = timeout.Value;              }              if (cookies != null)              {                  request.CookieContainer = new CookieContainer();                  request.CookieContainer.Add(cookies);              }              return request.GetResponse() as HttpWebResponse;          }          /// <summary>          /// 创建POST方式的HTTP请求          /// </summary>          /// <param name="url">请求的URL</param>          /// <param name="parameters">随同请求POST的参数名称及参数值字典</param>          /// <param name="timeout">请求的超时时间</param>          /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>          /// <param name="requestEncoding">发送HTTP请求时所用的编码</param>          /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>          /// <returns></returns>          public static HttpWebResponse CreatePostHttpResponse(string url,IDictionary<string,string> parameters,int? timeout, string userAgent,Encoding requestEncoding,CookieCollection cookies)          {              if (string.IsNullOrEmpty(url))              {                  throw new ArgumentNullException("url");              }              if(requestEncoding==null)              {                  throw new ArgumentNullException("requestEncoding");              }              HttpWebRequest request=null;              //如果是发送HTTPS请求              if(url.StartsWith("https",StringComparison.OrdinalIgnoreCase))              {                  ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);                  request = WebRequest.Create(url) as HttpWebRequest;                  request.ProtocolVersion=HttpVersion.Version10;              }              else             {                  request = WebRequest.Create(url) as HttpWebRequest;              }              request.Method = "POST";              request.ContentType = "application/x-www-form-urlencoded";                            if (!string.IsNullOrEmpty(userAgent))              {                  request.UserAgent = userAgent;              }              else             {                  request.UserAgent = DefaultUserAgent;              }               if (timeout.HasValue)              {                  request.Timeout = timeout.Value;              }              if (cookies != null)              {                  request.CookieContainer = new CookieContainer();                  request.CookieContainer.Add(cookies);              }              //如果需要POST数据              if(!(parameters==null||parameters.Count==0))              {                  StringBuilder buffer = new StringBuilder();                  int i = 0;                  foreach (string key in parameters.Keys)                  {                      if (i > 0)                      {                          buffer.AppendFormat("&{0}={1}", key, parameters[key]);                      }                      else                     {                          buffer.AppendFormat("{0}={1}", key, parameters[key]);                      }                      i++;                  }                  byte[] data = http://www.mamicode.com/requestEncoding.GetBytes(buffer.ToString());  "https://passport.baidu.com/?login";  string userName = "userName";  string password = "password";  string tagUrl = "http://cang.baidu.com/"+userName+"/tags";  Encoding encoding = Encoding.GetEncoding("gb2312");   IDictionary<string, string> parameters = new Dictionary<string, string>();  parameters.Add("tpl", "fa");  parameters.Add("tpl_reg", "fa");  parameters.Add("u", tagUrl);  parameters.Add("psp_tt", "0");  parameters.Add("username", userName);  parameters.Add("password", password);  parameters.Add("mem_pass", "1");  HttpWebResponse response = HttpWebResponseUtility.CreatePostHttpResponse(loginUrl, parameters, null, null, encoding, null);  string cookieString = response.Headers["Set-Cookie"];  （2）发送GET请求到HTTP站点 在cookieString中包含了服务器端返回的会话信息数据，从中提取了之后可以设置Cookie下次登录时带上这个Cookie就可以以认证用户的信息，假设我们已经登录成功并且获取了Cookie，那么发送GET请求的代码如下： string userName = "userName";  string tagUrl = "http://cang.baidu.com/"+userName+"/tags";  CookieCollection cookies = new CookieCollection();//如何从response.Headers["Set-Cookie"];中获取并设置CookieCollection的代码略  response = HttpWebResponseUtility.CreateGetHttpResponse(tagUrl, null, null, cookies);   (3)发送POST请求到HTTP站点 以登录51CTO为例： string loginUrl = "http://home.51cto.com/index.php?s=/Index/doLogin";  string userName = "userName";  string password = "password";   IDictionary<string, string> parameters = new Dictionary<string, string>();  parameters.Add("email", userName);  parameters.Add("passwd", password);   HttpWebResponse response = HttpWebResponseUtility.CreatePostHttpResponse(loginUrl, parameters, null, null, Encoding.UTF8, null);   在这里说句题外话，CSDN的登录处理是由http://passport.csdn.net/ajax/accounthandler.ashx这个Handler来处理的。  总结在本文只是讲解了在C#中发送请求到HTTP和HTTPS的用法，分GET/POST两种方式，为减少一些繁琐和机械的编码，周公将其封装为一个类，发送数据之后返回HttpWebResponse对象实例，利用这个实例我们可以获取服务器端返回的Cookie以便用认证用户的身份继续发送请求，或者读取服务器端响应的内容，不过在读取响应内容时要注意响应格式和编码，本来在这个类中还有读取HTML和WML内容的方法（包括服务器使用压缩方式传输的数据），但限于篇幅和其它方面的原因，此处省略掉了。如有机会，在以后的文章中会继续讲述这方面的内容。