Spring: Can I abstract my request mappings away to a base class?

Question

My Spring Boot application has a bunch of REST controller classes, all of which perform more or less the same standard CRUD operations on their respective models, just with different endpoint names (one is /user , one is /group , etc). It makes sense to pack this behaviour away in a base class, perhaps called Controller .

Firstly, is there a base class like this in Spring already, which I've missed? It seems like handy behaviour that lots of people would need, so I'm surprised I can't find it.

If not, and I need to write it myself, my problem is: what do I do with the request mapping annotations, like @GetMapping and @PostMapping ? Their value argument has to be constant, so I can't just use the annotations in the superclass and interpolate each endpoint name into them, as in @GetMapping("/" + endpointName + "/{id}") . Do I write my request-handling methods without the annotations, then wrap and annotate them in each of my 5-6 subclasses, like this?

@RestController
public abstract class Controller<T> {

    public ResponseEntity<T> create(T obj) {
        // Creation behaviour
    }

    // Same for retrieve, update, etc

}

...

public class UserController extends Controller<User> {

    @Override
    @PostMapping("/user")
    public ResponseEntity<User> create(@RequestBody User user) {
        return super.create(user);
    }

    // Repeat for other operations

}

// and repeat for all the other subclasses

It seems a little redundant; I'd love it if there was a cleaner way.

Answer 1

You can create a generic abstract controller for your CRUD mappings, like:

public abstract class AbstractGenericController<E extends yourGenericEntity> {
private static final Logger LOG = LoggerFactory.getLogger(AbstractGenericController.class);
@RequestMapping(value = "/create", method = RequestMethod.POST)
public ResponseEntity<GenericResult<T>> create(@RequestBody String input) {
// your process
}
@RequestMapping(value = "/update", method = RequestMethod.POST)
public ResponseEntity<GenericResult<T>> update(@RequestBody String input) {
// your process
}

Then your controller will extend the abstract controller.