实施REStful Web服务最佳实践？

Question

I am using Jersey Restful webservices.I have below end point.

@Path("/persons")
public class PersonWS {
    private final static Logger logger = LoggerFactory.getLogger(PersonWS.class);

    @Autowired
    private PersonService personService;

    @GET
    @Path("/{id}")
    @Produces({MediaType.APPLICATION_XML})
    public Person fetchPerson(@PathParam("id") Integer id) {
        return personService.fetchPerson(id);
    }

    @POST
    @Path("/add")
    @Consumes(MediaType.APPLICATION_XML)
    @Produces (MediaType.APPLICATION_XML)
    public Person addPerson(Person person) {
        personService.addPerson(person);
        return person;
    }
}

Above class does not implement any interface. Should i write a interface first and implement the methods of the interface in PersonWS.java? Or no need of writing any interface here?

Thanks!

Answer 1

The only point of having an interface is the option to provide a different implementation. Usually the only other implementation besides the main one is a mock used for testing. However, modern mocking frameworks will easily mock out your implementation class with no need for a separate interface.

In earlier times the interfaces were also necessary for techniques like method interceptors implemented with dynamic proxies (Spring AOP), but this requirement was obsoleted by load-time weaving and other modern techniques.

For these reasons I find the overhead of maintaining a duplicate of all your methods in an interface unjustified by any real benefit in modern application architectures.

Answer 2

The other reason to provide an interface is to allow to inject your controller in another one if needed (with spring for example) or if you want to share and distibute a contract of your application accross modules : your contract jar will contain domain and interfaces - without considering implementations and without the need to embed all your implementations in all your modules.

This could be consider as a good practice because it provides loose coupling and prepares evolving and growing but there is no technical need to provide an interface if you don't need it.