How to configuration rails upload directory in tomcat?

My basic requirement is upload and show image.
I use rails on jruby and warble package the project as war on windows.
In rails, I set my upload directory as
‘#{Rails.root}/public/data/users’. And it works on common rails light
server like webrick. But after I deployed to tomcat, the ‘public’
disappear. All the files under public went to the parent directory of
WEB-INF. And after the server started, the rails function can’t find the
Then I tried to move my ‘data’ directory back to WEB-INF, but the url
doesn’t work. I tried to create link in windows. But it still not works.
Can anybody suggestion some work around to do this? Thanks.