最后更新时间：2005年9月7日
更新了HttpDriver类
这个经过测试，使用上比较稳定，因为考虑到统一的错误处理，类里面没有catch任何错误，所有网络错误都在使用的时候捕获，以便决定重试或终止。支持get和post，支持自定义编码，支持cookie，但不支持上传文件。
Imports
System.Net
Imports
System.IO
Public
Class HttpDriver
Class HttpDriver Public Function GetPage()Function GetPage(ByVal url As String, Optional ByRef postPara As String = "", Optional ByRef encType As String = "GB2312") As String Return GetPage(url, postPara, Nothing, False, encType) End Function Public Function GetPage()Function GetPage(ByVal url As String, ByRef postPara As System.Collections.Hashtable, Optional ByRef encType As String = "GB2312") As String Return GetPage(url, ColToStr(postPara), encType) End Function Public Function GetPage()Function GetPage(ByVal url As String, ByRef postPara As String, ByRef cookies As CookieCollection, ByVal hasCookie As Boolean, Optional ByRef encType As String = "GB2312", Optional ByRef refer As String = "") As String If (url.StartsWith("http://") = False) Then url = "http://" & url End If Dim hRqst As HttpWebRequest = HttpWebRequest.Create(url) If (hasCookie = True AndAlso (Not cookies Is Nothing)) Then hRqst.CookieContainer = New CookieContainer hRqst.CookieContainer.Add(cookies) End If hRqst.ContentType = "application/x-www-form-urlencoded" hRqst.Headers.Add("Accept-Language", "zh-cn") Dim streamData As Stream Dim bt() As Byte If (postPara = "") Then hRqst.Method = "GET" Else hRqst.Method = "POST" hRqst.AllowWriteStreamBuffering = True bt = System.Text.Encoding.ASCII.GetBytes(postPara) hRqst.ContentLength = bt.Length hRqst.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)" hRqst.Referer = refer hRqst.KeepAlive = False hRqst.Timeout = 20000 streamData = hRqst.GetRequestStream() streamData.Write(bt, 0, bt.Length) streamData.Close() End If Dim hRsp As HttpWebResponse hRsp = hRqst.GetResponse() streamData = hRsp.GetResponseStream() If (hasCookie = True AndAlso (Not hRsp.Cookies Is Nothing)) Then cookies.Add(hRsp.Cookies) End If If (encType = "") Then encType = "GB2312" End If Dim readStream As New IO.StreamReader(streamData, System.Text.Encoding.GetEncoding(encType)) GetPage = readStream.ReadToEnd() streamData.Close() End Function Public Function GetPage()Function GetPage(ByVal url As String, ByRef postPara As System.Collections.Hashtable, ByRef cookies As CookieCollection, ByVal hasCookie As Boolean, Optional ByRef encType As String = "GB2312") As String Return GetPage(url, ColToStr(postPara), cookies, True, encType) End Function Public Function GetPage()Function GetPage(ByVal url As String, ByRef cookies As CookieCollection, ByVal hasCookie As Boolean, Optional ByRef encType As String = "GB2312") As String Return GetPage(url, "", cookies, True, encType) End Function '该函数用于转换表单项集合为字符串 Public Shared Function ColToStr()Function ColToStr(ByRef ht As System.Collections.Hashtable, Optional ByRef encType As String = "GB2312") As String Dim str As String Dim para As DictionaryEntry For Each para In ht str &= System.Web.HttpUtility.UrlEncode(CType(para.Key, String), Text.Encoding.GetEncoding(encType)) str &= "=" str &= System.Web.HttpUtility.UrlEncode(CType(para.Value, String), Text.Encoding.GetEncoding(encType)) str &= "&" Next str = str.Substring(0, str.Length - 1) Return str End FunctionEnd Class
如果需要支持cookie，并支持refer，可以通过下面这个类来使用上面的httpdriver。
'
该类用于访问含有cookie的页面
Imports
System.IO
Public
Class UserAgent
Class UserAgent Private m_cookies As New System.Net.CookieCollection Private refer As String Private hd As New HttpDriver Public Function GetPage()Function GetPage(ByVal url As String, Optional ByRef postPara As String = "", Optional ByRef encType As String = "GB2312") As String GetPage = hd.GetPage(url, postPara, m_cookies, True, encType, refer) refer = url End Function Public Function GetPage()Function GetPage(ByVal url As String, ByRef postPara As Hashtable, Optional ByRef encType As String = "GB2312") As String Return GetPage(url, hd.ColToStr(postPara), encType) End Function Public Function SetCookie()Function SetCookie(ByVal cookies As System.Net.CookieCollection) m_cookies = cookies End Function Public Function GetCookie()Function GetCookie() As System.Net.CookieCollection Return m_cookies End FunctionEnd Class
轻量的get网页的函数
Public
Function GetPage()
Function GetPage(ByVal url As String) As String Dim hRqst As HttpWebRequest = HttpWebRequest.Create(url) hRqst.ContentType = "application/x-www-form-urlencoded" hRqst.Method = "GET" Dim streamData As Stream Dim hRsp As HttpWebResponse = hRqst.GetResponse() streamData = hRsp.GetResponseStream() Dim readStream As New IO.StreamReader(streamData, System.Text.Encoding.GetEncoding("GB2312")) GetPage = readStream.ReadToEnd() streamData.Close()End Function
Get方法：
Dim
ua
as
New
UserAgent
Dim
content
as
String
Dim
url
as
String
url
=
"
www.sina.com.cn"
content
=
ua.GetPage(url) url = "sohu.com"content = ua.GetPage(url)
Post方法（页面和参数名字都是示例）。UserAgent的好处是可以透明的保存cookie，用以下的方法就可以实现登录后保存登录信息了。
Dim
ua
as
New
UserAgent
Dim
content
as
String
Dim
url
as
String
Dim
ht
as
New
HashTableurl
=
"
mail.sina.com.cn"
ht.Add(
"
username
"
,
"
用户名
"
)ht.Add(
"
password
"
,
"
密码
"
)content
=
ua.GetPage(url, ht) url = "mail.sina.com.cn/default.htm" content = ua.GetPage(url)
