You could use a filter. This url shows how to install a jar, and modify your web.xml:
http://tuckey.org/urlrewrite/
Your rewrite file would look like this:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE urlrewrite PUBLIC "-//tuckey.org//DTD UrlRewrite 3.2//EN"
"http://tuckey.org/res/dtds/urlrewrite3.2.dtd">
<urlrewrite>
<rule>
<name>pageName Redirect</name>
<from>^/pageName$</from>
<to>/somepage.html</to>
</rule>
</urlrewrite>
Edit:
My example does not change the URL in the users browser. It's form is helpful when you want more than one URL to show the same content.
If you want to change the URL, make this change to the code above:
<to type="redirect">/somepage.html</to>
Instead of sending the users browser content to display, this sends a message to the browser that the page has moved, and it should, transparently modify the browsers URL, and then load that page.
Difference between JSP forward and redirect