C#中HttpWebRequest的用法详解
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https://www.nhooo.com/?hl=zh-CN中，前面部分https://www.nhooo.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：
HttpWebRequestreq=(HttpWebRequest)HttpWebRequest.Create("https://www.nhooo.com?hl=zh-CN");
req.Method="GET";
using(WebResponsewr=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：
EncodingmyEncoding=Encoding.GetEncoding("gb2312");
stringaddress="https://www.nhooo.com/?"+HttpUtility.UrlEncode("参数一",myEncoding)+"="+HttpUtility.UrlEncode("值一",myEncoding);
HttpWebRequestreq=(HttpWebRequest)HttpWebRequest.Create(address);
req.Method="GET";
using(WebResponsewr=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https://www.nhooo.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：
stringparam="hl=zh-CN&newwindow=1";
byte[]bs=Encoding.ASCII.GetBytes(param);
HttpWebRequestreq=(HttpWebRequest)HttpWebRequest.Create("https://www.nhooo.com/");
req.Method="POST";
req.ContentType="application/x-www-form-urlencoded";
req.ContentLength=bs.Length;
using(StreamreqStream=req.GetRequestStream())
{
reqStream.Write(bs,0,bs.Length);
}
using(WebResponsewr=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https://www.nhooo.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：
EncodingmyEncoding=Encoding.GetEncoding("gb2312");
stringparam=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);
HttpWebRequestreq=(HttpWebRequest)HttpWebRequest.Create("https://www.nhooo.com/");
req.Method="POST";
req.ContentType="application/x-www-form-urlencoded;charset=gb2312";
req.ContentLength=postBytes.Length;
using(StreamreqStream=req.GetRequestStream())
{
reqStream.Write(bs,0,bs.Length);
}
using(WebResponsewr=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
usingSystem;
usingSystem.Collections.Generic;
usingSystem.IO;
usingSystem.Net;
usingSystem.Text;
namespaceHttpWeb
{
///<summary>
/// Http操作类
///</summary>
publicstaticclasshttptest
{
///<summary>
/// 获取网址HTML
///</summary>
///<paramname="URL">网址</param>
///<returns></returns>
publicstaticstringGetHtml(stringURL)
{
WebRequestwrt;
wrt=WebRequest.Create(URL);
wrt.Credentials=CredentialCache.DefaultCredentials;
WebResponsewrp;
wrp=wrt.GetResponse();
stringreader=newStreamReader(wrp.GetResponseStream(),Encoding.GetEncoding("gb2312")).ReadToEnd();
try
{
wrt.GetResponse().Close();
}
catch(WebExceptionex)
{
throwex;
}
returnreader;
}
///<summary>
///获取网站cookie
///</summary>
///<paramname="URL">网址</param>
///<paramname="cookie">cookie</param>
///<returns></returns>
publicstaticstringGetHtml(stringURL,outstringcookie)
{
WebRequestwrt;
wrt=WebRequest.Create(URL);
wrt.Credentials=CredentialCache.DefaultCredentials;
WebResponsewrp;
wrp=wrt.GetResponse();
stringhtml=newStreamReader(wrp.GetResponseStream(),Encoding.GetEncoding("gb2312")).ReadToEnd(); try { wrt.GetResponse().Close(); } catch(WebExceptionex) { throwex; } cookie=wrp.Headers.Get("Set-Cookie"); returnhtml; } publicstaticstringGetHtml(stringURL,stringpostData,stringcookie,outstringheader,stringserver) { returnGetHtml(server,URL,postData,cookie,outheader); } publicstaticstringGetHtml(stringserver,stringURL,stringpostData,stringcookie,outstringheader) { byte[]byteRequest=Encoding.GetEncoding("gb2312").GetBytes(postData); returnGetHtml(server,URL,byteRequest,cookie,outheader); } publicstaticstringGetHtml(stringserver,stringURL,byte[]byteRequest,stringcookie,outstringheader) { byte[]bytes=GetHtmlByBytes(server,URL,byteRequest,cookie,outheader); StreamgetStream=newMemoryStream(bytes); StreamReaderstreamReader=newStreamReader(getStream,Encoding.GetEncoding("gb2312")); stringgetString=streamReader.ReadToEnd(); streamReader.Close(); getStream.Close(); returngetString; } ///<summary> ///Post模式浏览 ///</summary> ///<paramname="server">服务器地址</param> ///<paramname="URL">网址</param> ///<paramname="byteRequest">流</param> ///<paramname="cookie">cookie</param> ///<paramname="header">句柄</param> ///<returns></returns> publicstaticbyte[]GetHtmlByBytes(stringserver,stringURL,byte[]byteRequest,stringcookie,outstringheader) { longcontentLength; HttpWebRequesthttpWebRequest; HttpWebResponsewebResponse; StreamgetStream; httpWebRequest=(HttpWebRequest)HttpWebRequest.Create(URL); CookieContainerco=newCookieContainer(); co.SetCookies(newUri(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;MSIE6.0;WindowsNT5.1;SV1;Maxthon;.NETCLR1.1.4322)"; httpWebRequest.Method="Post"; httpWebRequest.ContentLength=byteRequest.Length; Streamstream; 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=newbyte[contentLength]; outBytes=ReadFully(getStream); getStream.Close(); returnoutBytes; } publicstaticbyte[]ReadFully(Streamstream) { byte[]buffer=newbyte[128]; using(MemoryStreamms=newMemoryStream()) { while(true) { intread=stream.Read(buffer,0,buffer.Length); if(read<=0) returnms.ToArray(); ms.Write(buffer,0,read); } } } ///<summary> ///Get模式 ///</summary> ///<paramname="URL">网址</param> ///<paramname="cookie">cookies</param> ///<paramname="header">句柄</param> ///<paramname="server">服务器</param> ///<paramname="val">服务器</param> ///<returns></returns> publicstaticstringGetHtml(stringURL,stringcookie,outstringheader,stringserver) { returnGetHtml(URL,cookie,outheader,server,""); } ///<summary> ///Get模式浏览 ///</summary> ///<paramname="URL">Get网址</param> ///<paramname="cookie">cookie</param> ///<paramname="header">句柄</param> ///<paramname="server">服务器地址</param> ///<paramname="val"></param> ///<returns></returns> publicstaticstringGetHtml(stringURL,stringcookie,outstringheader,stringserver,stringval) { HttpWebRequesthttpWebRequest; HttpWebResponsewebResponse; StreamgetStream; StreamReaderstreamReader; stringgetString=""; httpWebRequest=(HttpWebRequest)HttpWebRequest.Create(URL); httpWebRequest.Accept="*/*"; httpWebRequest.Referer=server; CookieContainerco=newCookieContainer(); co.SetCookies(newUri(server),cookie); httpWebRequest.CookieContainer=co; httpWebRequest.UserAgent= "Mozilla/4.0(compatible;MSIE6.0;WindowsNT5.1;SV1;Maxthon;.NETCLR1.1.4322)"; httpWebRequest.Method="GET"; webResponse=(HttpWebResponse)httpWebRequest.GetResponse(); header=webResponse.Headers.ToString(); getStream=webResponse.GetResponseStream(); streamReader=newStreamReader(getStream,Encoding.GetEncoding("gb2312")); getString=streamReader.ReadToEnd(); streamReader.Close(); getStream.Close(); returngetString; } } }