HttpWebRequest的使用

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.studyofnet.com/?hl=zh-CN 中，前面部分 http://www.studyofnet.com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：  

C# 代码   复制

  HttpWebRequest req = (HttpWebRequest) HttpWebRequest.Create( "http://www.studyofnet.com?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：

 

C# 代码   复制

Encoding myEncoding = Encoding.GetEncoding("gb2312");

string address = "http://www.studyofnet.com/?" + 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 }

在上面的程序代码中，我们以 GET 方式访问了网址 http://www.studyofnet.com ，传递了参数“参数一=值一”，由于无法告知对方提交数据的编码类型，所以编码方式要以对方的网站为标准。

 

POST 方式

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：

 

C# 代码   复制

string param = "hl=zh-CN&newwindow=1";

byte[] bs = Encoding.ASCII.GetBytes(param);

HttpWebRequest req = (HttpWebRequest) HttpWebRequest.Create( "http://www.studyofnet.com/" );

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.studyofnet.com 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：  

C# 代码   复制

 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.studyofnet.com/" );

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 }

从上面的代码可以看出， POST 中文数据的时候，先使用 UrlEncode 方法将中文字符转换为编码后的 ASCII 码，然后提交到服务器，提交的时候可以说明编码的方式，用来使对方服务器能够正确的解析。  

用C#语言写的关于HttpWebRequest 类的使用方法

 

C# 代码   复制

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; } } }