VB Post方式提取网页数据

VB Post方式提取网页数据 [转贴 2006-4-20 20:17:33]   

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    Public Function getDataAsHtml(ByVal url As String, ByVal postData As String, ByVal modifyCook As Boolean)
        '构造请求头
        Try
            Dim httpUrl As New System.Uri(url) '生成URL类
            Dim req As HttpWebRequest '创建HTTP请求实例
            req = CType(WebRequest.Create(httpUrl), HttpWebRequest)
            req.CookieContainer = currentCookies
            req.Timeout = 600000

            '构造POST数据
            req.Method = "POST" '设置请求方式
            req.ContentType = "application/x-www-form-urlencoded"
            Dim ParameterEncoding As Encoding = System.Text.Encoding.GetEncoding("GB2312") '设置编码方式
            Dim bytesData As Byte() = ParameterEncoding.GetBytes(postData) '获取POST数据
            req.ContentLength = bytesData.Length '获取数据长度
            req.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; Maxthon; SV1; .NET CLR 1.1.4322)"
            req.Accept = "*.*"
            req.ProtocolVersion = HttpVersion.Version11

            '发送HTTP请求
            Dim postStream As Stream = req.GetRequestStream()
            postStream.Write(bytesData, 0, bytesData.Length)   '以上向服务器post信息。
            postStream.Close()

            '读取返回信息

            Dim res As HttpWebResponse = CType(req.GetResponse(), HttpWebResponse) '以下获取服务器返回信息
            Dim reader As StreamReader = _
            New StreamReader(res.GetResponseStream, System.Text.Encoding.GetEncoding("GB2312"))
            currentHTML = reader.ReadToEnd()

            '测试返回信息
            'MsgBox(currentHTML)
            If modifyCook = True Then
                Dim cook As Cookie
                For Each cook In res.Cookies
                    currentCookies.Add(cook)
                    If cook.Name = "JSESSIONID" Then
                        sessionID = cook.Value.Substring(4, 23)
                    End If
                    If cook.Name = "EBankNetBank2001" Then
                        usera = cook.Value
                    End If
                Next cook
            End If

            '关闭
            res.Close()
            Return currentHTML
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Function

参数说明，url---网址，postData---所要执行的动作及参数，modifyCook---是否改变本地的cookies。