i have sure that almost all will look to this thread and think : newbie.

What do you think about a architecture like that:
Every Controller will have a BusinessRule class associated. The business Rule will throws exceptions when some error happen, this exception will be catched by the controller that must change the screen flow.
So if a exception occur in the business Rule, like UserNotFoundException, the controller will change the web flow.
This approach is correct, based-exception screen flow ?

thanks to all