Well, using URL will be really hard, 'cos your controller maps requests using URL mappings and if you change them you might get into trouble.
But, if you want to try something different, the first place to look is the LocaleResolver interface, it's the interface you will have to implement to change the way that a Locale is choosen: http://static.springframework.org/sp...eResolver.html
Take a look at the avaliable implementations, don't try to write a new one if one of the avaliable classes suit your needs (one of them will probably do, but none use URL to resolve it).
Coding: At the end of the day, if the program doesn\'t run and make money for the client, you haven\'t done anything.