A common way to customize JSON representations with Jackson is to register mixin types. The currently most convenient way is to declare a Module implementation that the calls setMixInAnnotation(…) on the module. The module itself can be exposed as a bean and will be picked up by Boot. That registration code is quite a bit of boilerplate to be written and could be simplified as follows:

  1. Introduce an annotation @JsonMixin(Foo.class) that would be added to the mixin type. Foo is the target type the mixin is registered for.
  2. Boot could find classes annotated with @JsonMixin and register a module that registers all mixin types declared like this for the type declared in the annotation.

I.e. a plain declaration of this:

@JsonMixin(MyType.class)
abstract class MyMixin { /* … */ }

would replace

@Configuration
class MyConfiguration {

  @Bean 
  Module myModule() {
    return new MixinModule(Map.of(MyType.class, MyMixin.class));
  }
}

class MixinModule extends SimpleModule {

 MixinModule(Map<Class<?>, Class<?>> mixins) {
    mixins.entrySet().forEach(it -> setMixInAnnotation(it.getKey(), it.getValue()));
  }
}

Comment From: philwebb

This would align quite nicely with the existing @JsonComponent support.

Comment From: wilkinsona

Thanks very much for the offer, @Tharik67. Please go ahead and let us know if you have any questions. It's a little too late for new features in next month's 2.6 release, but if you were able to open a PR we'd hope to include it in 2.7.

Comment From: wilkinsona

Closing in favor of #30152.