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) = "" ThenOutputErr "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_FileExts_FileExt = Mid(s_DownFilePath, InstrRev(s_DownFilePath, ".")+1)If InStr("," & ALLOW_FILE_EXT & ",", "," & s_FileExt & ",") <= 0 ThenOutputErr "错误：文件类型（" & s_FileExt & "）不允许被下载，下载失败"End Ifs_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fsoDim o_FsoOn Error Resume NextSet o_Fso = Server.CreateObject("Scripting.FileSystemObject")If Err.Number <> 0 ThenErr.ClearOutputErr "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_FileMapPathDim o_File, s_FileName, n_FileLengths_FileMapPath = Server.MapPath(s_DownFilePath)If (o_Fso.FileExists(s_FileMapPath)) = True ThenSet o_File = o_Fso.GetFile(s_FileMapPath)s_FileName = o_File.Namen_FileLength = o_File.Sizeo_File.CloseElseOutputErr "错误：文件不存在，下载失败"End IfSet 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 ThenResponse.Redirect sDownFilePathResponse.endEnd If'检测服务器是否支持Adodb.StreamOn Error Resume NextSet o_Stream = Server.CreateObject("Adodb.Stream")If Err.Number <> 0 ThenErr.ClearOutputErr "错误：服务器不支持Adodb.Stream组件，下载失败"End Ifo_Stream.Tyep = 1o_Stream.Openo_Stream.LoadFromFile s_FileMapPath Response.Buffer = TrueResponse.ClearResponse.AddHeader "Content-Disposition", "attachment; filename=" & s_FileNameResponse.AddHeader "Content-Length", n_FileLength Response.CharSet = "UTF-8" Response.ContentType = "application/octet-stream" Response.BinaryWrite o_Stream.ReadResponse.Flusho_Stream.CloseSet o_Stream = NothingEnd FunctionSub OutputErr(s_ErrMsg)Response.Write "<font color=red>" & s_ErrMsg & "</font>" Response.EndEnd Sub%>