Parse jar:file prefix to Resource

Hi,

I am writing some custom ant tasks and I want to support files inside of
zip/jar files. I have noticed that some ant tasks use the
jar:file:/path/to/a.jar!/path/in/jar/file.xml syntax but I can't seem to
get it work. How do I use this pattern in my tasks and map them to a
Resource object like FileResource, URLResource, etc. Thanks.

Matt Bertolini