asp文件下载

 <%
If Not IsNull(Request("fileName")) Then r = DownLoadFile(Request("fileName"))
Function DownLoadFile(fileName)
Dim s,fso,f,fLen
fileName = Server.MapPath(fileName)
'create stream
Set s = Server.CreateObject("ADODB.Stream")
s.Open()
s.Type = 1
Set fso = Server.CreateObject("Scripting.FileSystemObject")

If Not fso.FileExists(fileName) Then Response.Write "文件不存在" : Response.End
Set f = fso.GetFile(fileName)
fLen = f.Size
s.LoadfromFile(fileName)

'clear the buffer
Response.Buffer = True
Response.Clear()
Response.AddHeader"Content-Disposition","attachment;filename=" & f.name
Response.AddHeader"Content-Length",fLen
Response.CharSet = "UTF-8"
Response.ContentType = "application/octet-stream"
'output the file to the browser
Response.BinaryWrite s.Read
Response.Flush


s.Close
Set s = Nothing
Set fso = Nothing
End Function
%>