c# HttpWebRequest与HttpWebResponse 绝技

1.第一招，根据URL地址获取网页信息

   先来看一下代码

get方法

  public   static   string  GetUrltoHtml( string  Url, string  type)
        {
             try
            {
                System.Net.WebRequest wReq  =  System.Net.WebRequest.Create(Url);
                 //  Get the response instance.
                System.Net.WebResponse wResp  =  wReq.GetResponse();
                System.IO.Stream respStream  =  wResp.GetResponseStream();
                 //  Dim reader As StreamReader = New StreamReader(respStream)
                using (System.IO.StreamReader reader = new System.IO.StreamReader(respStream, Encoding.GetEncoding(type)))
                {
                    return reader.ReadToEnd();
                }
            }
             catch  (System.Exception ex)
            {
                 // errorMsg = ex.Message;
            }
             return   "" ;
        }

post方法

   /// <summary>
         /// 采用https协议访问网络
         /// </summary>
         /// <param name="URL"> url地址 </param>
         /// <param name="strPostdata"> 发送的数据 </param>
         /// <returns></returns>
         public   string  OpenReadWithHttps( string  URL,  string  strPostdata,  string  strEncoding)
        {
            Encoding encoding  =  Encoding.Default;
            HttpWebRequest request  =  (HttpWebRequest)WebRequest.Create(URL);
            request.Method  =   " post " ;
            request.Accept  =   " text/html, application/xhtml+xml, */* " ;
            request.ContentType  =   " application/x-www-form-urlencoded " ;
             byte [] buffer  =  encoding.GetBytes(strPostdata);
            request.ContentLength  =  buffer.Length;
            request.GetRequestStream().Write(buffer,  0 , buffer.Length);
            HttpWebResponse response  =  (HttpWebResponse)request.GetResponse();
            using( StreamReader reader  =   new  StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding(strEncoding)))

              {
                    return  reader.ReadToEnd();

              }
        }

这招是入门第一式， 特点：

   1.最简单最直观的一种，入门课程。

   2.适应于明文，无需登录，无需任何验证就可以进入的页面。

   3.获取的数据类型为HTML文档。

   4.请求方法为Get/Post

2.第二招，根据URL地址获取需要验证证书才能访问的网页信息

   先来看一下代码

 get方法

   // 回调验证证书问题
         public   bool  CheckValidationResult( object  sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
        {    //  总是接受    
             return   true ;
        }

         ///   <summary>
         ///  传入URL返回网页的html代码
         ///   </summary>
         ///   <param name="Url"> URL </param>
         ///   <returns></returns>
         public   string  GetUrltoHtml( string  Url)
        {
            StringBuilder content  =   new  StringBuilder();

             try
            {
                 // 这一句一定要写在创建连接的前面。使用回调的方法进行证书验证。
                ServicePointManager.ServerCertificateValidationCallback  =   new  System.Net.Security.RemoteCertificateValidationCallback(CheckValidationResult);

                 //  与指定URL创建HTTP请求
                HttpWebRequest request  =  (HttpWebRequest)WebRequest.Create(Url);

                 // 创建证书文件
                X509Certificate objx509  =   new  X509Certificate(Application.StartupPath  +   " \\123.cer " );

                 // 添加到请求里
                request.ClientCertificates.Add(objx509);

                 //  获取对应HTTP请求的响应
                HttpWebResponse response  =  (HttpWebResponse)request.GetResponse();
                 //  获取响应流
                Stream responseStream  =  response.GetResponseStream();
                 //  对接响应流(以"GBK"字符集)
                StreamReader sReader  =   new  StreamReader(responseStream, Encoding.GetEncoding( " utf-8 " ));
                 //  开始读取数据
                Char[] sReaderBuffer  =   new  Char[ 256 ];
                 int  count  =  sReader.Read(sReaderBuffer,  0 ,  256 );
                 while  (count  >   0 )
                {
                    String tempStr  =   new  String(sReaderBuffer,  0 , count);
                    content.Append(tempStr);
                    count  =  sReader.Read(sReaderBuffer,  0 ,  256 );
                }
                 //  读取结束
                sReader.Close();
            }
             catch  (Exception)
            {
                content  =   new  StringBuilder( " Runtime Error " );
            }

             return  content.ToString();

        }