[C#]基于HttpWebRequest和HttpWebResponse的HttpHelper

C#中实现POST的方法很多，常用的是WebBrowser、WebClient、HttpWebRequest和HttpWebResponse。

1、WebBrowser基本是在DocumentCompleted中分析HtmlDocument ；

2、WebClient是对HttpWebRequest和HttpWebResponse的封装，用起来更方便，但是灵活性还是不及HttpWebRequest和HttpWebResponse；

3、HttpWebRequest和HttpWebResponse更底层，灵活度更好，不过代码更多，我做了一个简单的封装，将GET改成分段读取，并加入代理、进度条和错误重试处理。代码如下：



using System;

using System.IO;

using System.Net;

using System.Text;

namespace Van.Base

{

public class HttpHelper

{

#region 委托 事件

public delegate void dgtProgValueChanged(long Value);

/// <summary>

/// 进度改变事件

/// </summary>

public event dgtProgValueChanged OnProgValueChanged;

#endregion

#region 属性

/// <summary>

/// 代理

/// </summary>

public WebProxy Proxy { get; set; }

/// <summary>

/// Cookie

/// </summary>

public CookieContainer UserCookie { get; set; }

/// <summary>

/// 重试次数

/// </summary>

public int IAfreshTime { get; set; }

/// <summary>

/// 错误次数

/// </summary>

public int IErrorTime { get; private set; }

long m_ProgValue = 0;

/// <summary>

/// 当前读取字节

/// </summary>

public long ProgValue

{

get { return m_ProgValue; }

private set

{

m_ProgValue = value;

if (OnProgValueChanged != null)

{

OnProgValueChanged(value);

}

}

}

/// <summary>

/// 待读取最大字节

/// </summary>

public long ProgMaximum { get; private set; }

#endregion

#region 方法

#region Get

/// <summary>

/// 获取HTML

/// </summary>

/// <param name="URL">地址</param>

/// <param name="Accept">Accept请求头</param>

/// <returns>Html代码</returns>

public string GetHTML(string URL, string Accept)

{

return GetHTML(URL, Accept, System.Text.Encoding.UTF8);

}

/// <summary>

/// 获取HTML

/// </summary>

/// <param name="URL">地址</param>

/// <param name="Accept">Accept请求头</param>

/// <param name="encoding">字符编码</param>

/// <returns>Html代码</returns>

public string GetHTML(string URL, string Accept, Encoding encoding)

{

return GetHTML(URL, Accept, encoding, 1024);

}

/// <summary>

/// 获取HTML

/// </summary>

/// <param name="URL">地址</param>

/// <param name="Accept">Accept请求头</param>

/// <param name="encoding">字符编码</param>

/// <param name="bufflen">数据包大小</param>

/// <returns>Html代码</returns>

public string GetHTML(string URL, string Accept, Encoding encoding, int bufflen)

{

IErrorTime = 0;

return _GetHTML(URL, Accept, encoding, bufflen);

}

/// <summary>

/// 获取HTML

/// </summary>

/// <param name="URL">地址</param>

/// <param name="Accept">Accept请求头</param>

/// <param name="encoding">字符编码</param>

/// <param name="bufflen">数据包大小</param>

/// <returns>Html代码</returns>

private string _GetHTML(string URL, string Accept, Encoding encoding,int bufflen)

{

try

{

HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);

MyRequest.Proxy = Proxy;

MyRequest.Accept = Accept;

if (UserCookie == null)

{

UserCookie = new CookieContainer();

}

MyRequest.CookieContainer = UserCookie;

HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();

return _GetHTML(MyResponse, encoding, bufflen);

}

catch (Exception erro)

{

if (erro.Message.Contains("连接") && IAfreshTime - IErrorTime > 0)

{

IErrorTime++;

return _GetHTML(URL, Accept, encoding, bufflen);

}

throw;

}

}

/// <summary>

/// 获取HTML

/// </summary>

/// <param name="MyResponse"></param>

/// <param name="encoding">字符编码</param>

/// <param name="bufflen">数据包大小</param>

/// <returns></returns>

private string _GetHTML(HttpWebResponse MyResponse, Encoding encoding, int bufflen)

{

using (Stream MyStream = MyResponse.GetResponseStream())

{
ProgMaximum = MyResponse.ContentLength;

string result = null;

long totalDownloadedByte = 0;

byte[] by = new byte[bufflen];

int osize = MyStream.Read(by, 0, by.Length);

while (osize > 0)

{

totalDownloadedByte = osize + totalDownloadedByte;

result += encoding.GetString(by, 0, osize);

ProgValue = totalDownloadedByte;

osize = MyStream.Read(by, 0, by.Length);

}

MyStream.Close();

return result;

}

}

#endregion

#region GetImg

public System.Drawing.Bitmap Getimg(string URL, string Accept)

{

return _GetBit(URL, Accept);

}

/// <summary>

/// 获取HTML

/// </summary>

/// <param name="URL">地址</param>

/// <param name="Accept">Accept请求头</param>

/// <returns>Html代码</returns>

private System.Drawing.Bitmap _GetBit(string URL, string Accept)

{

HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);

MyRequest.Proxy = Proxy;

MyRequest.Accept = Accept;

if (UserCookie == null)

{

UserCookie = new CookieContainer();

}

MyRequest.CookieContainer = UserCookie;

HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();

return _GetBit(MyResponse);

}

/// <summary>

/// 获取图像

/// </summary>

/// <param name="MyResponse"></param>

/// <returns></returns>

private System.Drawing.Bitmap _GetBit(HttpWebResponse MyResponse)

{

using (Stream MyStream = MyResponse.GetResponseStream())

{

return new System.Drawing.Bitmap(MyStream);

}

}

#endregion

#region Post

/// <summary>

/// 回发(字符编码默认UTF-8)

/// </summary>

/// <param name="URL">回发地址</param>

/// <param name="PostData">参数</param>

/// <returns>Html代码</returns>

public string PostPage(string URL, string PostData)

{

return PostPage(URL, PostData, System.Text.Encoding.UTF8);

}

/// <summary>

/// 回发

/// </summary>

/// <param name="URL">回发地址</param>

/// <param name="PostData">参数</param>

/// <param name="encoding">字符编码</param>

/// <returns>Html代码</returns>

public string PostPage(string URL, string PostData, Encoding encoding)

{

return PostPage(URL, PostData, encoding, null);

}

/// <summary>

/// 回发

/// </summary>

/// <param name="URL">回发地址</param>

/// <param name="PostData">参数</param>

/// <param name="encoding">字符编码</param>

/// <returns>Html代码</returns>

public string PostPage(string URL, string PostData, Encoding encoding, string ContentType)

{

IErrorTime = 0;

return _PostPage(URL, PostData, encoding, ContentType);

}

/// <summary>

/// 回发

/// </summary>

/// <param name="URL">回发地址</param>

/// <param name="PostData">参数</param>

/// <param name="encoding">字符编码</param>

/// <returns>Html代码</returns>

private string _PostPage(string URL, string PostData, Encoding encoding,string ContentType)

{

try

{

if (ContentType==null)

{

ContentType = "application/x-www-form-urlencoded";

}

HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);

MyRequest.Proxy = Proxy;

if (UserCookie == null)

{

UserCookie = new CookieContainer();

}

MyRequest.CookieContainer = UserCookie;

MyRequest.Method = "POST";

MyRequest.ContentType = ContentType;

byte[] b = encoding.GetBytes(PostData);

MyRequest.ContentLength = b.Length;

using (System.IO.Stream sw = MyRequest.GetRequestStream())

{

try

{

sw.Write(b, 0, b.Length);

}

catch

{

}

}

HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();

return _GetHTML(MyResponse, encoding, 1024);

}

catch (Exception erro)

{

if (erro.Message.Contains("连接") && IAfreshTime - IErrorTime > 0)

{

IErrorTime++;

return _PostPage(URL, PostData, encoding, ContentType);

}

throw;

}

}

#endregion

#endregion

}

}



调用便很方便了，如下：



string strProxyAdd = "www.Proxyxxxx.com", UserName = "XXXX",PassWord = "XXX";

int port = 8080;

HttpHelper http = new HttpHelper();

http.Proxy = new WebProxy();//设置代理

this.http.Proxy.Address = new Uri(string.Format("http://{0}:{1}", strProxyAdd,port));//设置代理服务器地址和端口

this.http.Proxy.Credentials = new NetworkCredential(UserName, PassWord);//设置代理用户名密码

//http.Proxy = null;//清空代理

var strPHtml = http.PostPage("www.xxxx.com", "User=ABCD&Pwd=DEF");//向www.xxxx.com POST数据User=ABCD&Pwd=DEF

var strHtml = http.GetHTML("www.xxxx.com", "*/*", Encoding.UTF8, 20480);//从www.xxxx.com获取HTML数据，并用UTF8进行编码

由于Cookie在一个实例中是共用的，在一些场景下可以先POST登录后再GET需要登录才能进入的页面信息。

来源：http://www.cnblogs.com/vanjoge/archive/2011/11/18/2253937.html