JAX-RS — How to return JSON and HTTP status code together?

Question

I'm writing a REST web app (NetBeans 6.9, JAX-RS, TopLink Essentials) and trying to return JSON and HTTP status code. I have code ready and working that returns JSON when the HTTP GET method is called from the client. Essentially:

@Path("get/id")
@GET
@Produces("application/json")
public M_機械 getMachineToUpdate(@PathParam("id") String id) {

    // some code to return JSON ...

    return myJson;
}

But I also want to return an HTTP status code (500, 200, 204, etc.) along with the JSON data.

I tried to use HttpServletResponse:

response.sendError("error message", 500);

But this made the browser think it's a "real" 500 so the output web page was a regular HTTP 500 error page.

I want to return an HTTP status code so that my client-side JavaScript can handle some logic depending on it (to e.g. display the error code and message on an HTML page). Is this possible or should HTTP status codes not be used for such thing?

Answer 1

Here's an example:

@GET
@Path("retrieve/{uuid}")
public Response retrieveSomething(@PathParam("uuid") String uuid) {
    if(uuid == null || uuid.trim().length() == 0) {
        return Response.serverError().entity("UUID cannot be blank").build();
    }
    Entity entity = service.getById(uuid);
    if(entity == null) {
        return Response.status(Response.Status.NOT_FOUND).entity("Entity not found for UUID: " + uuid).build();
    }
    String json = //convert entity to json
    return Response.ok(json, MediaType.APPLICATION_JSON).build();
}

Take a look at the Response class.

Note that you should always specify a content type, especially if you are passing multiple content types, but if every message will be represented as JSON, you can just annotate the method with @Produces("application/json")