vb.net用来获取网页的类

Imports System.Net

Imports System.IO

Public Class HttpDriverClass 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 Function

End 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 UserAgentClass 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 Function

End 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)

Post方法：

Dim ua as New UserAgent

Dim content as String

Dim url as String

Dim ht as New HashTable

url = "mail.sina.com.cn"

ht.Add("username", "用户名")

ht.Add("password", "密码")

content = ua.GetPage(url, ht)