Considering moving from Java/Spring MVC to Grails

Question

I'm currently using Java & Spring (MVC) to create a webapp, and I'm considering moving to Grails. I'd appreciate feedback/insight on the following:

1. I have multiple application contexts in the current Java/Spring webapp that I load through the web.xml ContextLoaderListener; is it possible to have multiple application contexts in Grails? If, yes, how?

2. This webapp extensively uses a CXF restful web service and the current Java/Spring webapp uses the bundled CXF HTTP client. Can I continue to use the (Java) CXF HTTP Client in Grails?

3. I implemented Spring Security using a custom implementation of UserDetails and UserDetailsService, can I re-use these implementations in Grails "as is" or must I re-implement them?

4. There is an instance where I've relied on Spring's jdbc template (rather than the available ORM) and an additional data source I defined in app context, can I re-use this in Grails?

5. I plan on using Maven as the project management tool; are there any issues of using Maven with Grails where there is a combination of groovy and java?

Edit: I'm considering moving to Grails to make the development of the web component of the webapp "faster," a la Ruby-on-Rails. Also, I'm considering Grails rather than say Ruby-on-Rails, because I want to continue to use the JVM and I've dabbled with Grails in the past and it was fairly easy to pick-up and use.

Answer 1

1. Probably. Grails uses a sub-class of Spring's ContextLoaderListener class which it configures in the web.xml file. I can answer more precisely if you let me know how you do it with Spring MVC.

2. Yes. You might even be interested in the CXF plugin, although I can't vouch for it:

   http://grails.org/plugin/cxf

3. You should be able to use them as-is. However, you might want to check whether this is easily done with the Spring Security plugin. I believe it is, but you'll be able to get a definitive answer from Burt Beckwith, the author of the plugin.

4. Yes. You can also get hold of the Hibernate session factory to do raw Hibernate stuff. GORM can also work with multiple data sources:

   http://grails.org/plugin/datasources

   Another Burt Beckwith one :)

5. It depends on what you mean by "a combination of Groovy and Java". You can build Grails projects with Maven, but the integration isn't entirely smooth. If you have Java and Groovy in your Grails project, then that's taken care of automatically.

In response to Bozho, I use standard Grails services + GORM and wouldn't do it any other way. Note that if you use Java for services and the domain model, you won't have automatic reloading of services. You also lose the benefits of expressiveness and conciseness that Groovy bring.

If you want, you can use static types in Grails services to make it easier for your IDE to provide code completion. It can also give you hints on properties and methods it doesn't recognise (which would corresponding to Java compilation errors). That said, even if you use static types, Groovy can't do type checks at compilation time. You'll only find out about them at runtime.