原作:possible_Y,載自時代課堂

在瀏覽器的地址欄里直接輸入一個doc或xls或jpg的文件的url路徑，那么該文件會直接顯示在瀏覽器里。而在很多時候我們希望能直接彈出下載提示框讓用戶下載，我們該怎么辦呢？這里有兩種方法：
1、設置你的服務器的iis，給doc等后綴名做映射
2、在向客戶端發送時設置其contenttype

下面詳細說明方法2

<%
Response.Buffer = true
Response.Clear

dim url
Dim fso,fl,flsize
dim Dname
Dim objStream,ContentType,flName,isre,url1
'*********************************************調用時傳入的下載文件名
Dname=trim(request("n"))
'******************************************************************
If Dname<>"" Then
'******************************下載文件存放的服務端目錄
 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

%>

將下面的東西存成download.asp然后你就可以用<a herf="http://www.knowsky.com/download.asp?n=file.doc">download!</a>來下載同一目錄下的file.doc了!

但是這里有個問題就是直接將file.doc路徑寫在url里是不安全的，所以解決方案應該是將file.doc的路徑存到數據庫里，同過查找數據庫后得到路徑

在這個程序的最前面如果加上一個判斷：

if instr(Request.ServerVariables("HTTP_REFERER"),"http://你的域名")=0 then
  Response.End
end if

就能夠很好的防止別人的盜鏈了