我写的一个asp上传组件

　　网上流传的种种asp上传类真是太烦琐了，我自己写了一个上传类。这个上传类体积很小，只适用于单文件上传，返回结果是一个json，格式为：{"err":"出错原因","msg":"上传文件的地址"}，例如：{"err":"\u6587\u4EF6\u592A\u5927\u4E86\2C\u4E0A\u4F20\u6587\u4EF6\u4E0D\u80FD\u8D85\u8FC7200K","msg":""}
或者{"err":"","msg":"uploadfile/201013/7897896786.zip"}
<%@LANGUAGE="VBSCRIPT" CODEPAGE="936"%>
<%Option Explicit
Response.Buffer = True
response.charset = "gb2312"
Const uploadfolder="uploadpic"
Const allowExt="jpg,jpeg,gif,png,rar,doc,zip,xls,pdf,swf,avi,mp3,txt,htm,html"
Function BytestoStr(filestr)
dim skipflag : skipflag = 0
dim varlen,clow,i
dim content : content = ""
if not isnull(filestr) then
varlen = lenb(filestr)
for i=1 to varlen
if skipflag=0 then
clow = midb(filestr,i,1)
if ascb(clow) > 127 then
content = content & chr(ascw(midb(filestr,i+1,1) & clow))
skipflag = 1
else
content = content & chr(ascb(clow))
end if
else
skipflag = 0
end if
next
end if
BytestoStr = content
End Function
Function getFilepath(ext)
dim folderpath,fso,filename
folderpath=server.mappath(uploadfolder)
set fso=server.createobject("Scripting.FileSystemObject")
if Fso.FolderExists(folderpath)=false then fso.CreateFolder(folderpath)
folderpath=folderpath&"\"&replace(replace(date(),"/",""),"-","")
fileinfo=uploadfolder&date()
if Fso.FolderExists(folderpath)=false then fso.CreateFolder(folderpath)
filename=cstr(timer()*100)&"."&ext
getFilepath=folderpath&"\"&filename
fileinfo=fileinfo&"/"&filename
set Fso=nothing
End Function
Function CheckExt(fileinfo)
dim re
set re=new