Providing RESTful JSON API in Java

Question

What is the idiomatic way of providing RESTful JSON API in Java? Do you use JAX-WS and XML annotations (@XmlElement etc.)? How do you serialize annotated objects to JSON (using Jackson or similar library)? How do you separate domain objects from objects sent out to API?

I know Java, I would like you to point me out to good resources and best practices about these topics.

Thank you!

Answer 1

I have used happily Jersey/JAX-RS but I would suggest you Spring MVC 3, not only for the rest api support but also for other interesting stuff as IoC or beans that could turn out to be useful.

Here a link where to refer: http://blog.springsource.org/2009/03/08/rest-in-spring-3-mvc/

Btw, I've used Jackson with Spring as parser. :)

---

A bit of code (basically mark your bean, as you said, with @XmlRootElement and use @Path to mark the API)

JAX-RS

bean:

@XmlRootElement
public class Response {

  private String result;
  private String message;

  //getter and setter
}

api:

@Path("rest/user")
@Produces(MediaType.APPLICATION_JSON)
public class UserService {

  @POST
  @Path("/login")
  public Response login(
        @FormParam("username") String username,
        @FormParam("password") String password
  ) {
      // Your logic here
  }
}

Spring

api:

@Controller
@RequestMapping("/user")
public class UserService {

  @RequestMapping(method = RequestMethod.POST, value="/login", headers="Accept=application/json")
  public @ResponseBody Response login(
        @RequestParam(value = "user", defaultValue = "") String email,
        @RequestParam(value = "password", defaultValue = "") String password,
        HttpServletRequest request
        ) {
    // Your logic here
  }
}

Answer 2

I would simply use Play to save me a lot of work that has already been done. The link is for Play 1.2 and while the current version is 2.1, it should be fit for that as well.