浅谈C#中HttpWebRequest与HttpWebResponse的使用方法

2019-12-30 15:47:04王冬梅

这个类是专门为HTTP的GET和POST请求写的,解决了编码,证书,自动带Cookie等问题。

C# HttpHelper,帮助类,真正的Httprequest请求时无视编码,无视证书,无视Cookie,网页抓取

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>
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>
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();
}