Both of them use MVC and Groovy. Thus, there is not enough adaptation in the code.
I think the main changes you will need are the following:
- Separating requests from game models and placing them on Grails services.
- Overwrite application configuration files and data.
- Display Url.
This is not much work compared to rewriting the entire project.
On the other hand, you have to be careful with GORM and its database administration, because it is different from JPA.
UPDATE!
Just taken from a blog post.
Plugins / Modules
Grails: Grails has Grails plugins. They are just awesome. And the way they are organized on the site is also very good. It is very important for me to see the ratings. Unfortunately there are no reviews - it would be useful to read reviews about different plugins. I used at least two plugins - Spring security plugin and Searchable plugin. Spring security worked like a charm, although I had to spend some time setting it up on old database tables. The Searchable plugin worked so-so. Whatever I did, I couldn’t tweak the search results (or maybe I didn’t spend enough time?). I spent at least one evening browsing the plugin catalog and thinking, “yeah, I need this plugin for some time in the future. And this one too. And that!”.
Play: Play Framework has a similar concept of plugins - modules. Some functionality is already included in the main modules of Play and Play are not at all different from plugins. Except - the catalog of modules does not show ratings or reviews, so it will be more difficult for you to make a choice - you are on your own, accept your risk when choosing one or another module.
Who will win: Grails
Here you have the original message.
In any case, I think there are a few more Grails plugins than Playframework modules. But this is just a thought, and I have not tested it.
Hope this helps :)