asp文件缓存,从缓存读数据实例

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从文件读数据,要比直接从数据库快,测试读出6000条新闻,读数据库用了23579毫秒,读文件只用了123毫秒,下例为使用文件缓存的代码 
使用方法,在需要使用文件缓存的页面加入下列代码,
<!--#include file="FileCatch.asp" -->
<%
Set MyCatch=new CatchFile
MyCatch.Overdue=10     ’修改过期时间设置为10分钟
if MyCatch.CatchNow(Rev) then
        response.write MyCatch.CatchData
        response.end
end if
set MyCatch=nothing

%>
FileCatch.asp
复制内容到剪贴板代码:
<%
’ 本文件用于签入原始文件,实现对页面的文件Catch
’ 1、如果文件请求为POST方式,则取消此功能
’ 2、文件的请求不能包含系统的识别关键字
Class CatchFile
        Public Overdue,Mark,CFolder,CFile ’定义系统参数
        Private ScriptName,ScriptPath,ServerHost ’定义服务器/页面参数变量
        Public CatchData        ’输出的数据
        Private Sub Class_Initialize        ’初始化函数
                ’获得服务器及脚本数据
                ScriptName=Request.Servervariables("Script_Name") ’识别出当前脚本的虚拟地址
                ScriptPath=GetScriptPath(false)        ’识别出脚本的完整GET地址
                ServerHost=Request.Servervariables("Server_Name") ’识别出当前服务器的地址
                ’初始化系统参数
                Overdue=30        ’默认30分钟过期
                Mark="NoCatch"        ’无Catch请求参数为 NoCatch
                CFolder=GetCFolder        ’定义默认的Catch文件保存目录
                CFile=Server.URLEncode(ScriptPath)&".txt"        ’将脚本路径转化为文件路径
                CatchData=""
        end Sub
        Private Function GetCFolder
                dim FSO,CFolder
                Set FSO=CreateObject("Scripting.FileSystemObject")        ’设置FSO对象
                CFolder=Server.MapPath("/")&"/FileCatch/"
                if not FSO.FolderExists(CFolder) then
                        fso.CreateFolder(CFolder)
                end if
                if Month(Now())<10 then
                        CFolder=CFolder&"/0"&Month(Now())
                else
                        CFolder=CFolder&Month(Now())
                end if
                if Day(Now())<10 then
                        CFolder=CFolder&"0"&Day(Now())
                else
                        CFolder=CFolder&Day(Now())
                end if
                CFolder=CFolder&"/"
                if not FSO.FolderExists(CFolder) then
                        fso.CreateFolder(CFolder)
                end if
                GetCFolder=CFolder
                set fso=nothing
        End Function
        Private Function bytes2BSTR(vIn)        ’转换编码的函数
                dim StrReturn,ThisCharCode,i,NextCharCode
                strReturn = ""
                For i = 1 To LenB(vIn)
                        ThisCharCode = AscB(MidB(vIn,i,1))
                        If ThisCharCode < &H80 Then
                                strReturn = strReturn & Chr(ThisCharCode)
                        Else
                                NextCharCode = AscB(MidB(vIn,i+1,1))
                                strReturn = strReturn & Chr(CLng(ThisCharCode) * &H100 + CInt(NextCharCode))
                                i = i + 1
                        End If
                Next
                bytes2BSTR = strReturn
        End Function
        Public Function CatchNow(Rev)        ’用户指定开始处理Catch操作
                if UCase(request.Servervariables("Request_Method"))="POST" then
                ’当是POST方法,不可使用文件Catch
                        Rev="使用POST方法请求页面,不可以使用文件Catch功能"
                        CatchNow=false
                else
                        if request.Querystring(Mark)<>"" then
                        ’如果指定参数不为空,表示请求不可以使用Catch
                                Rev="请求拒绝使用Catch功能"
                                CatchNow=false
                        else
                                CatchNow=GetCatchData(Rev)
                        end if
                end if
        End Function
        Private Function GetCatchData(Rev)        ’读取Catch数据
                Dim FSO,IsBuildCatch
                Set FSO=CreateObject("Scripting.FileSystemObject")        ’设置FSO对象,访问CatchFile
                If FSO.FileExists(CFolder&CFile) Then
                        Dim File,LastCatch
                        Set File=FSO.GetFile(CFolder&CFile)        ’定义CatchFile文件对象
                        LastCatch=CDate(File.DateLastModified)
                        if DateDiff("n",LastCatch,Now())>Overdue then
                        ’如果超过了Catch时间
                                IsBuildCatch=true
                        else
                                IsBuildCatch=false
                        end if
                        Set File=Nothing
                else
                        IsBuildCatch=true
                End if
                If IsBuildCatch then
                        GetCatchData=BuildCatch(Rev)        ’如果需要创建Catch,则创建Catch文件,同时设置Catch的数据
                else
                        GetCatchData=ReadCatch(Rev)        ’如果不需要创建Catch,则直接读取Catch数据
                End if
                Set FSO=nothing
        End Function
        Private Function GetScriptPath(IsGet)        ’创建一个包含所有请求数据的地址
                dim Key,Fir
                GetScriptPath=ScriptName
                Fir=true
                for Each key in Request.QueryString
                        If Fir then
                                GetScriptPath=GetScriptPath&"?"
                                Fir=false
                        else
                                GetScriptPath=GetScriptPath&"&"
                        end if
                        GetScriptPath=GetScriptPath&Server.URLEncode(Key)&"="&Server.URLEncode(Request.QueryString(Key))
                Next
                if IsGet then
                        If Fir then
                                GetScriptPath=GetScriptPath&"?"
                                Fir=false
                        else
                                GetScriptPath=GetScriptPath&"&"
                        end if
                        GetScriptPath=GetScriptPath&Server.URLEncode(Mark)&"=yes"
                end if
        End Function
        ’创建Catch文件
        Private Function BuildCatch(Rev)
                Dim HTTP,Url,OutCome
                Set HTTP=CreateObject("Microsoft.XMLHTTP")
’                On Error Resume Next
’                response.write ServerHost&GetScriptPath(true)
                HTTP.Open "get","http://"&ServerHost&GetScriptPath(true),False
                HTTP.Send
                if Err.number=0 then
                        CatchData=bytes2BSTR(HTTP.responseBody)
                        BuildCatch=True
                else
                        Rev="创建发生错误:"&Err.Description
                        BuildCatch=False
                        Err.clear
                end if
                Call WriteCatch
                set HTTP=nothing
        End Function
        Private Function ReadCatch(Rev)
                ReadCatch=IReadCatch(CFolder&CFile,CatchData,Rev)
        End Function
        Private Sub WriteCatch
                Dim FSO,TSO
                Set FSO=CreateObject("Scripting.FileSystemObject")        ’设置FSO对象,访问CatchFile
                set TSO=FSO.CreateTextFile(CFolder&CFile,true)
                TSO.Write(CatchData)
                Set TSO=Nothing
                Set FSO=Nothing
        End Sub
End Class
Function IReadCatch(File,Data,Rev)
        Dim FSO,TSO
        Set FSO=CreateObject("Scripting.FileSystemObject")        ’设置FSO对象,访问CatchFile
’        on error resume next
        set TSO=FSO.OpenTextFile(File,1,false)
        Data=TSO.ReadAll
        if Err.number<>0 then
                Rev="读取发生错误:"&Err.Description
                ReadCatch=False
                Err.clear
        else
                IReadCatch=True
        end if
        Set TSO=Nothing
        Set FSO=Nothing
End Function
%>

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