输出文件的下载

<%
Response.Buffer = true
Response.Clear

 dim url
 Dim fso,fl,flsize
 dim Dname
 Dim objStream,ContentType,flName,isre,url1
'*********************************************调用时传入的下载文件名
 Dname=trim(request("n"))
'******************************************************************
 If Dname<>"" Then
'******************************下载文件存放的服务端目录
  url=server.MapPath("/")&"/"&Dname
'***************************************************
 End If

 Set fso=Server.CreateObject("Scripting.FileSystemObject")
  Set fl=fso.getfile(url)
  flsize=fl.size
  flName=fl.name
  Set fl=Nothing
  Set fso=Nothing
 %>
 <%
  Set objStream = Server.CreateObject("ADODB.Stream")
  objStream.Open
  objStream.Type = 1
  objStream.LoadFromFile url

   Select Case lcase(Right(flName, 4))
    Case ".asf"
     ContentType = "video/x-ms-asf"
    Case ".avi"
     ContentType = "video/avi"
    Case ".doc"
     ContentType = "application/msword"
    Case ".zip"
     ContentType = "application/zip"
    Case ".xls"
     ContentType = "application/vnd.ms-excel"
    Case ".gif"
     ContentType = "image/gif"
    Case ".jpg", "jpeg"
     ContentType = "image/jpeg"
    Case ".wav"
     ContentType = "audio/wav"
    Case ".mp3"
     ContentType = "audio/mpeg3"
    Case ".mpg", "mpeg"
     ContentType = "video/mpeg"
    Case ".rtf"
     ContentType = "application/rtf"
    Case ".htm", "html"
     ContentType = "text/html"
    Case ".txt"
     ContentType = "text/plain"
    Case Else
     ContentType = "application/octet-stream"
   End Select

 

   Response.AddHeader "Content-Disposition", "attachment; filename=" & flName
   Response.AddHeader "Content-Length", flsize

   Response.Charset = "UTF-8"
   Response.ContentType = ContentType

   Response.BinaryWrite objStream.Read
   Response.Flush
   response.Clear()
  objStream.Close
  Set objStream = Nothing

%>