implement dynamic filter

[lanxiazhi]

hello,
I have a web app in tomcat ,where exists some .jsp,.vm files,
these files are saved using different encoding(I think).when requested,some
of them display urgly,garbled.
so I think maybe I can implement such a filter:first read the content of the
file,and* *decide which charset it's saved,and set the ServletResponse's
character encoding accordingly.
Is that possible ? If possible ,how to decide the charset quickly ,without
slowing down the server?
thanks
lanxiazhi