获取网络时间实例

时　间:2014-01-18 13:16:37
作　者:杜超-2号   ID：16058  城市：江阴
摘　要:计算机的时间不准，或其它原因我们需要从网络中获得准确的时间和日期，以此做了个简单示例
正　文:

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Function NetTime(Optional url As String) As String  '返回包括时间和日期的字符串

   Dim obj, OBJStatus,  Retrieval  

   Dim GetText As String

   Dim i As Long   

   Dim myDate As Date

   Set Retrieval = CreateObject("Microsoft.XMLHTTP")  

    If url = "" Then      

            url = "http://www.time.ac.cn/stime.asp" '从国家授时中心网页获取时间

    End If

   '通过下载网页头信息获取网络时间

   On Error Goto ToExit       

   With Retrieval

            .Open "Get", url, False, "", ""

            .setRequestHeader "If-Modified-Since", "0"

            .setRequestHeader "Cache-Control", "no-cache"

            .setRequestHeader "Connection", "close"

            .Send

            If .Readystate <> 4 Then Exit Function

            GetText = .getAllResponseHeaders()

            i = InStr(1, GetText, "date:", vbTextCompare)

           If i > 0 Then  '网页下载成功

                i = InStr(i, GetText, ",", vbTextCompare)

                GetText = Trim(Mid(GetText, i + 1))

                i = InStr(1, GetText, " GMT", vbTextCompare)

               GetText = Left(GetText, i - 1)

                myDate = GetText '字符串变为时间类型

                myDate = myDate + #8:00:00 AM#   '将时间转化为北京时间

                NetTime = myDate  '将时间转化为字符串

            End If

        End With

ToExit:

    Set Retrieval = Nothing

    Set OBJStatus = Nothing

    Set obj = Nothing

End Function