Advice needed on best way of persisting and changing web.xml valuesfor service continuity

[milesd]

Hello, I am currently refactoring a Java servlet/JSP based website
which has no concept of failing over to different databases or search
servers. The "live servers" are specified in tomcat web.xml and are
visible as part of servlet context.

I would like to implement a secure way of manually changing the live
servers to alternative servers which will allow for continuity. I had
thought of the following:

Specify the alternative servers in web.xml. Persist them in a
stateful bean. Let the user access the bean and "flip a switch" which
will allow the alternate server to be selected.

The only issue with this approach is that there are six separate
applications each with an individual web.xml

I would prefer to use a framework such as hibernate or spring to
develop the "flip a switch" functionality.

I have never developed this type of thing and would appreciate some
advice on developing this easily without over complicating things.

thanks

Miles.