VB.net 获取网页源码
方法一
Public Function getWebSource(ByVal url As String) As String
Try
Dim stream As IO.Stream = WebRequest.Create(url).GetResponse().GetResponseStream()
Dim sr As StreamReader = New StreamReader(stream, System.Text.Encoding.UTF8)
Return sr.ReadToEnd()
Catch ex As Exception
Return ""
'Return ex.ToString()
End Try
End Function
方法二
节选自网络,实测较慢
Public Function GetWebCode(ByVal strURL As String) As String
Dim httpReq As System.Net.HttpWebRequest
Dim httpResp As System.Net.HttpWebResponse
Dim httpURL As New System.Uri(strURL)
Dim ioS As System.IO.Stream, charSet As String, tCode As String
Dim k() As Byte
ReDim k(0)
Dim dataQue As New Queue(Of Byte)
httpReq = CType(WebRequest.Create(httpURL), HttpWebRequest)
Dim sTime As Date = CDate("1990-09-21 00:00:00")
httpReq.IfModifiedSince = sTime
httpReq.Method = "GET"
httpReq.Timeout = 7000
Try
httpResp = CType(httpReq.GetResponse(), HttpWebResponse)
Catch
Debug.Print("weberror")
GetWebCode = "<title>no thing found</title>" : Exit Function
End Try
'以上为网络数据获取
ioS = CType(httpResp.GetResponseStream, Stream)
Do While ioS.CanRead = True
Try
dataQue.Enqueue(ioS.ReadByte)
Catch
Debug.Print("read error")
Exit Do
End Try
Loop
ReDim k(dataQue.Count - 1)
For j As Integer = 0 To dataQue.Count - 1
k(j) = dataQue.Dequeue
Next
'以上,为获取流中的的二进制数据
tCode = Encoding.GetEncoding("UTF-8").GetString(k) '获取特定编码下的情况,毕竟UTF-8支持英文正常的显示
charSet = Replace(GetByDiv2(tCode, "charset=", """"), """", "") '进行编码类型识别
'以上,获取编码类型
If charSet = "" Then 'defalt
If httpResp.CharacterSet = "" Then
tCode = Encoding.GetEncoding("UTF-8").GetString(k)
Else
tCode = Encoding.GetEncoding(httpResp.CharacterSet).GetString(k)
End If
Else
tCode = Encoding.GetEncoding(charSet).GetString(k)
End If
Debug.Print(charSet)
'Stop
'以上,按照获得的编码类型进行数据转换
'将得到的内容进行最后处理,比如判断是不是有出现字符串为空的情况
GetWebCode = tCode
If tCode = "" Then GetWebCode = "<title>no thing found</title>"
End Function
Public Function GetByDiv2(ByVal code As String, ByVal divBegin As String, ByVal divEnd As String) '获取分隔符所夹的内容[完成,未测试]
'仅用于获取编码数据
Dim lgStart As Integer
Dim lens As Integer
Dim lgEnd As Integer
lens = Len(divBegin)
If InStr(1, code, divBegin) = 0 Then GetByDiv2 = "" : Exit Function
lgStart = InStr(1, code, divBegin) + CInt(lens)
lgEnd = InStr(lgStart + 1, code, divEnd)
If lgEnd = 0 Then GetByDiv2 = "" : Exit Function
GetByDiv2 = Mid(code, lgStart, lgEnd - lgStart)
End Function