asp 下载函数

N久没搞ASP啦,今天一个网友问到这个问题.就在网上找了下.

也不知道这个有没有错误.

下载的基本思路是这个样子的.

代码如下:

<%Const USE_STREAM = 0 '0.不用流(Adodb.Stream)下载 1.用流下载Const ALLOW_FILE_EXT = "rar,zip,chm,doc,xls,swf,mp3,gif,jpg,jpeg,png,bmp" '允许下载的文件的扩展名，防止源代码被下载Dim sDownFilePath '下载文件路径sDownFilePath = Trim(Request("FilePath"))'或者根据传过来的文件ID从数据库中获取文件路径'如果 sDownFilePath 为绝对路径，一定要将 sDownFilePath 转换为相对 本文件的相对路径'sDownFilePath = "focus.swf"Call DownloadFile(sDownFilePath)Function DownloadFile(s_DownFilePath)    '判断有没传递文件名    If IsNull(s_DownFilePath) = True Or Trim(s_DownFilePath) = "" Then        OutputErr "错误：先确定要下载的文件，下载失败"    End If    '判断扩展名是否合法    Dim s_FileExt    s_FileExt = Mid(s_DownFilePath, InstrRev(s_DownFilePath, ".")+1)    If InStr("," & ALLOW_FILE_EXT & ",", "," & s_FileExt & ",") <= 0 Then        OutputErr "错误：文件类型（" & s_FileExt & "）不允许被下载，下载失败"    End If        s_DownFilePath = Replace(s_DownFilePath, "/", "/")    '为了安全，某些目录禁止下载文件，在这里处理    '        '检测服务器是否支持fso    Dim o_Fso    On Error Resume Next    Set o_Fso = Server.CreateObject("Scripting.FileSystemObject")    If Err.Number <> 0 Then        Err.Clear        OutputErr "错误：服务器不支持fso组件，下载失败"    End If    '取得文件名，文件大小    Dim s_FileMapPath    Dim o_File, s_FileName, n_FileLength    s_FileMapPath = Server.MapPath(s_DownFilePath)    If (o_Fso.FileExists(s_FileMapPath)) = True Then        Set o_File = o_Fso.GetFile(s_FileMapPath)        s_FileName = o_File.Name        n_FileLength = o_File.Size        o_File.Close    Else        OutputErr "错误：文件不存在，下载失败"    End If    Set o_Fso = Nothing    '判断是否下载的文件大小超过限制    '            '如果不是用流下载，直接转到该文件    If USE_STREAM = 0 Then        Response.Redirect sDownFilePath        Response.end    End If    '检测服务器是否支持Adodb.Stream    On Error Resume Next    Set o_Stream = Server.CreateObject("Adodb.Stream")    If Err.Number <> 0 Then        Err.Clear        OutputErr "错误：服务器不支持Adodb.Stream组件，下载失败"    End If    o_Stream.Tyep = 1    o_Stream.Open    o_Stream.LoadFromFile s_FileMapPath     Response.Buffer = True    Response.Clear    Response.AddHeader "Content-Disposition", "attachment; filename=" & s_FileName    Response.AddHeader "Content-Length", n_FileLength     Response.CharSet = "UTF-8"     Response.ContentType = "application/octet-stream"     Response.BinaryWrite o_Stream.Read    Response.Flush    o_Stream.Close    Set o_Stream = NothingEnd FunctionSub OutputErr(s_ErrMsg)    Response.Write "<font color=red>" & s_ErrMsg & "</font>"     Response.EndEnd Sub%>