There is absolutely no reason to extend the dispatcher to do anything with Hibernate; this kind of thing is precisely what interceptors are for.
I'm assuming you're taking about creating an open-session-in-view-/OPSiV-style solution. Whether or not this is always the best solution is debatable; naive usage can lead to unexpected loss of performance in JSP pages due to lazy initialization.
Personally, I've switched over to using Spring's transaction support (there are similar solutions besides Spring) and have found it pretty handy. I also tend to initialize only the data I know will be used in the JSP to avoid the aforementioned performance hits, but part of that is due to some of the complicated data structures I've worked with lately and their expensive SQL queries.
Joined: Jan 30, 2009
Now thinking to learn spring for this integration purpose.