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本文实例讲述了C#中HttpWebRequest的用法。分享给大家供大家参考。具体如下：

HttpWebRequest类主要利用HTTP 协议和服务器交互，通常是通过 GET 和 POST 两种方式来对数据进行获取和提交。下面对这两种方式进行一下说明：

GET 方式：
GET 方式通过在网络地址附加参数来完成数据的提交，比如在地址 http://www.jb51.net/?hl=zh-CN 中，前面部分 http://www.jb51.net表示数据提交的网址，后面部分 hl=zh-CN 表示附加的参数，其中 hl 表示一个键(key)， zh-CN 表示这个键对应的值(value)。
程序代码如下： 

HttpWebRequest req = (HttpWebRequest) HttpWebRequest.Create( "http://www.jb51.net?hl=zh-CN" );
req.Method = "GET";
using (WebResponse wr = req.GetResponse())
{
//在这里对接收到的页面内容进行处理
}

使用 GET 方式提交中文数据。

GET 方式通过在网络地址中附加参数来完成数据提交，对于中文的编码，常用的有 gb2312 和 utf8 两种。
用 gb2312 方式编码访问的程序代码如下：

Encoding myEncoding = Encoding.GetEncoding("gb2312");
string address = "http://www.jb51.net/?" + HttpUtility.UrlEncode("参数一", myEncoding) + "=" + HttpUtility.UrlEncode("值一", myEncoding);
HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(address);
req.Method = "GET";
using (WebResponse wr = req.GetResponse())
{
//在这里对接收到的页面内容进行处理
}

POST 方式通过在页面内容中填写参数的方法来完成数据的提交，参数的格式和 GET 方式一样，是类似于 hl=zh-CN&newwindow=1 这样的结构。
程序代码如下：

string param = "hl=zh-CN&newwindow=1";
byte[] bs = Encoding.ASCII.GetBytes(param);
HttpWebRequest req = (HttpWebRequest) HttpWebRequest.Create( "http://www.jb51.net/" );
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.ContentLength = bs.Length;
using (Stream reqStream = req.GetRequestStream())
{reqStream.Write(bs, 0, bs.Length);
}
using (WebResponse wr = req.GetResponse())
{//在这里对接收到的页面内容进行处理
}

在上面的代码中，我们访问了 http://www.jb51.net 的网址，分别以 GET 和 POST 方式提交了数据，并接收了返回的页面内容。然而，如果提交的参数中含有中文，那么这样的处理是不够的，需要对其进行编码，让对方网站能够识别。 
使用 POST 方式提交中文数据
POST 方式通过在页面内容中填写参数的方法来完成数据的提交，由于提交的参数中可以说明使用的编码方式，所以理论上能获得更大的兼容性。
用 gb2312 方式编码访问的程序代码如下： 

Encoding myEncoding = Encoding.GetEncoding("gb2312");
string param = HttpUtility.UrlEncode("参数一", myEncoding) + "=" + HttpUtility.UrlEncode("值一", myEncoding) + "&" + HttpUtility.UrlEncode("参数二", myEncoding) + "=" + HttpUtility.UrlEncode("值二", myEncoding);
byte[] postBytes = Encoding.ASCII.GetBytes(param);
HttpWebRequest req = (HttpWebRequest) HttpWebRequest.Create( "http://www.jb51.net/" );
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded;charset=gb2312";
req.ContentLength = postBytes.Length;
using (Stream reqStream = req.GetRequestStream())
{reqStream.Write(bs, 0, bs.Length);
}
using (WebResponse wr = req.GetResponse())
{//在这里对接收到的页面内容进行处理
}

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;
namespace HttpWeb
{/// <summary>///  Http操作类/// </summary>public static class httptest{/// <summary>///  获取网址HTML/// </summary>/// <param name="URL">网址 </param>/// <returns> </returns>public static string GetHtml(string URL){WebRequest wrt;wrt = WebRequest.Create(URL);wrt.Credentials = CredentialCache.DefaultCredentials;WebResponse wrp;wrp = wrt.GetResponse();string reader = new StreamReader(wrp.GetResponseStream(), Encoding.GetEncoding("gb2312")).ReadToEnd();try{wrt.GetResponse().Close();}catch (WebException ex){throw ex;}return reader;}/// <summary>/// 获取网站cookie/// </summary>/// <param name="URL">网址 </param>/// <param name="cookie">cookie </param>/// <returns> </returns>public static string GetHtml(string URL, out string cookie){WebRequest wrt;wrt = WebRequest.Create(URL);wrt.Credentials = CredentialCache.DefaultCredentials;WebResponse wrp;wrp = wrt.GetResponse();string html = new StreamReader(wrp.GetResponseStream(), Encoding.GetEncoding("gb2312")).ReadToEnd();try{wrt.GetResponse().Close();}catch (WebException ex){throw ex;}cookie = wrp.Headers.Get("Set-Cookie");return html;}public static string GetHtml(string URL, string postData, string cookie, out string header, string server){return GetHtml(server, URL, postData, cookie, out header);}public static string GetHtml(string server, string URL, string postData, string cookie, out string header){byte[] byteRequest = Encoding.GetEncoding("gb2312").GetBytes(postData);return GetHtml(server, URL, byteRequest, cookie, out header);}public static string GetHtml(string server, string URL, byte[] byteRequest, string cookie, out string header){byte[] bytes = GetHtmlByBytes(server, URL, byteRequest, cookie, out header);Stream getStream = new MemoryStream(bytes);StreamReader streamReader = new StreamReader(getStream, Encoding.GetEncoding("gb2312"));string getString = streamReader.ReadToEnd();streamReader.Close();getStream.Close();return getString;}/// <summary>/// Post模式浏览/// </summary>/// <param name="server">服务器地址 </param>/// <param name="URL">网址 </param>/// <param name="byteRequest">流 </param>/// <param name="cookie">cookie </param>/// <param name="header">句柄 </param>/// <returns> </returns>public static byte[] GetHtmlByBytes(string server, string URL, byte[] byteRequest, string cookie, out string header){long contentLength;HttpWebRequest httpWebRequest;HttpWebResponse webResponse;Stream getStream;httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(URL);CookieContainer co = new CookieContainer();co.SetCookies(new Uri(server), cookie);httpWebRequest.CookieContainer = co;httpWebRequest.ContentType = "application/x-www-form-urlencoded";httpWebRequest.Accept ="image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*";httpWebRequest.Referer = server;httpWebRequest.UserAgent ="Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon; .NET CLR 1.1.4322)";httpWebRequest.Method = "Post";httpWebRequest.ContentLength = byteRequest.Length;Stream stream;stream = httpWebRequest.GetRequestStream();stream.Write(byteRequest, 0, byteRequest.Length);stream.Close();webResponse = (HttpWebResponse)httpWebRequest.GetResponse();header = webResponse.Headers.ToString();getStream = webResponse.GetResponseStream();contentLength = webResponse.ContentLength;byte[] outBytes = new byte[contentLength];outBytes = ReadFully(getStream);getStream.Close();return outBytes;}public static byte[] ReadFully(Stream stream){byte[] buffer = new byte[128];using (MemoryStream ms = new MemoryStream()){while (true){int read = stream.Read(buffer, 0, buffer.Length);if (read <= 0)return ms.ToArray();ms.Write(buffer, 0, read);}}}/// <summary>/// Get模式/// </summary>/// <param name="URL">网址 </param>/// <param name="cookie">cookies </param>/// <param name="header">句柄 </param>/// <param name="server">服务器 </param>/// <param name="val">服务器 </param>/// <returns> </returns>public static string GetHtml(string URL, string cookie, out string header, string server){return GetHtml(URL, cookie, out header, server, "");}/// <summary>/// Get模式浏览/// </summary>/// <param name="URL">Get网址 </param>/// <param name="cookie">cookie </param>/// <param name="header">句柄 </param>/// <param name="server">服务器地址 </param>/// <param name="val"> </param>/// <returns> </returns>public static string GetHtml(string URL, string cookie, out string header, string server, string val){HttpWebRequest httpWebRequest;HttpWebResponse webResponse;Stream getStream;StreamReader streamReader;string getString = "";httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(URL);httpWebRequest.Accept = "*/*";httpWebRequest.Referer = server;CookieContainer co = new CookieContainer();co.SetCookies(new Uri(server), cookie);httpWebRequest.CookieContainer = co;httpWebRequest.UserAgent ="Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon; .NET CLR 1.1.4322)";httpWebRequest.Method = "GET";webResponse = (HttpWebResponse)httpWebRequest.GetResponse();header = webResponse.Headers.ToString();getStream = webResponse.GetResponseStream();streamReader = new StreamReader(getStream, Encoding.GetEncoding("gb2312"));getString = streamReader.ReadToEnd();streamReader.Close();getStream.Close();return getString;}}
}

希望本文所述对大家的C#程序设计有所帮助。

原文地址：http://www.jb51.net/article/57156.htm