Have you considered the Play framework? Or Wicket?
The Java Frankenstack frameworks leave me cold (and most of the web development community also), but Play and Wicket are trying to bring Java back to the web.
You also have good tutorials for getting play to work on Heroku, so you can easily test out your deployments.
Other than that, I am biased, but you should look into the Ruby frameworks: Rails, Sinatra or Padrino. Sinatra plays really nicely on JRuby, and Padrino bolts on lots of features to it. Rails has huge amount of documentation and resources.
I wouldn't be a fan of a PHP based solution unless you were building around one of the main CMS systems (Wordpress, Drupal, Joomla).