JAX-RS如何序列化嵌入在公共包装器对象中的JSON对象，并在不使用包装器的情况下反序列化

Question

I intend to send JSON data to my JAX-RS endpoints like so:

POST /myendpoint

{
  "field1": "something",
  "field2": "something else",
  "field3": 12345
}

Then when I retrieve an object I want it contained in a common wrapper:

GET /myendpoint

{
  "type": "MyEndpoint"
  "items": [
    {
      "item":     {
        "id": 1,
        "field1": "something",
        "field2": "something else",
        "field3": 12345
      },
      "link": "https://api.site.com/myendpoint/1"
    },
    {
      "item":     {
        "id": 2,
        "field1": "different",
        "field2": "different else",
        "field3": 67890
      },
      "link": "https://api.site.com/myendpoint/2"
    }
  ],
  "page_size": 10,
  "page": 1,
  "total": 2,
  "message": ""
}

And

GET /myendpoint/2

{
  "type": "MyEndpoint"
  "items": [
    {
      "item":     {
        "id": 2,
        "field1": "different",
        "field2": "different else",
        "field3": 67890
      },
      "link": "https://api.site.com/myendpoint/2"
    }
  ],
  "page_size": 10,
  "page": 1,
  "total": 1,
  "message": ""
}

I am starting to use Jackson FasterXML in Jersey for automatic serialisation/deserialisation, ie:

@Provider
public class JsonObjectMapperProvider implements ContextResolver<ObjectMapper> {

    private final ObjectMapper objectMapper;

    public JsonObjectMapperProvider() {
        objectMapper = new ObjectMapper();
    }

    @Override
    public ObjectMapper getContext(final Class<?> type) {
        return objectMapper;
    }

}

And then in the resources:

@POST
@Consumes(MediaType.APPLICATION_JSON)
public void createMyEndpoint(MyEndpoint myEndpoint) {
    myEndpointDao.create(myEndpoint);
    // ...
}

@GET
@Produces(MediaType.APPLICATION_JSON)
public List<MyEndpoint> createMyEndpoint() {
    // I'm not actually sure how to do this one yet!! but I include it for completeness
    return myEndpointDao.getAll();
}

@GET
@Path("{id}")
@Produces(MediaType.APPLICATION_JSON)
public MyEndpoint createMyEndpoint(@PathParam("{id}") id) {
    return myEndpointDao.read(id);
}

This would work for MyEndpoint objects that aren't contained in the wrapper but how would I include the wrapper? Or is there an altogether better way to do this?

The schema for the JSON isn't set in stone, if something else makes more sense then I'm all ears.

Answer 1

Here I write few suggestion I have in mind reading your question:

1. return always something from your methods, even if you're handling a POST method. This will make the caller aware of request status.
2. instead of return your model objects, I think is better if your methods return always an object javax.ws.rs.core.Response
3. if you're worried about the serialization (I mean the use of the wrapper) just use the Response object to serialize your response. For example for a success response use: Response.ok().entity(yourReturnObject).build() , this will care of the serialization part almost transparently (you don't need to handle the objectMapper).

This could be a trivial example of a method:

@GET
@Path("/{id}")
@Produces({ "application/json" })
public Response createMyEndpoint(@PathParam("id") String id) {
    try {
        return Response.ok().entity(myEndpointDao.read(id)).build();
    } catch (Exception e) {
       Response.status(500).entity(e.getMessage()).build();
    }
}

I also suggest, to make you're life simpler, have a look at swagger .