Grails 3 and Spring Java Config

The Spring Java config is a great way to work with Spring configuration. It feels similar to Google Guice, which I personally enjoy. Mr. Haki did a great write up on using it with Grails 2.4.

While working with Grails 3 there are a few areas that don’t have plugins yet but do have Spring modules we can leverage. So I started out with the same path given for Grails 2.X.

application.yml

grails:
    profile: web
    codegen:
        defaultPackage: example
    spring:
        bean:
            packages:
                - example.config

I found that while the beans were all wired correctly and @Autowired all worked correctly, but any mappings with @RequestMapping where always returning a 404. Everything looked wired correctly but Grails wasn’t letting any requests through.

So I switched over to using @ComponentScan then the requests were properly mapped and everything started working.

Using ComponentScan with Grails 3 is very easy:

Application.groovy

@ComponentScan("example.config")
class Application extends GrailsAutoConfiguration {
  //...
}

This will scan the package of example.config for any Spring components so your Spring Java configs can all live in this package and easily get picked up.

This post is the blog form of this SO Question.