I'm using the UrlRewriteFilter library in order to avoid having to write my own url filter.
I'm pretty sure that I have things set up properly, because when I have this in my url rewrite xml:
<rule>
<from>^/urlIWantToMap</from>
<to type="redirect">/WhereIWouldLikeItToGo</to>
</rule>
It seems to work fine (as in, hitting http://localhost:8080/urlIWantToMap sends me to the intended location). Note that I had to add the servlet mapping to my web.xml.
If I try this though...
<rule>
<from>^/urlIWantToMap</from>
<run class="mypackage.MyServletClass" method="doGet"/>
</rule>
I get an http 404. I think it is the same kind of problem described here (even though I'm suspicious on the solution/resolution the author comes to):
http://greatwebguy.com/programming/java/urlrewritefilter-servlet-filter-problem-in-websphere-6105-and-greater/
I can see this happening if there were some kind of change to web filter behavior that would inhibit UrlRewriteFilter from calling into the servlet. Either that; or I'm making a blatant mistake I'm not seeing.