How to dynamically remove fields from a json response?

Question

I\'m using spring to create a restful api, so far so good, my question is how to model the fields that go to the response dynamically?

Thats the controller that i\'m

Answer 1

I'm struggling with this requirement, too.

The following code is a workaround using the JsonViews already mentioned by @beerbajay in the comment to your question:

http://wiki.fasterxml.com/JacksonJsonViews

I'm using Spring Boot 1.2.3.

Views.java

package demo;

public class Views {

    static interface Public {}

    static interface Internal extends Public {}
}

Album.java

package demo;

import com.fasterxml.jackson.annotation.JsonView;

public class Album {

    @JsonView(Views.Public.class)
    private String id;

    @JsonView(Views.Public.class)
    private String title;

    @JsonView(Views.Public.class)
    private String artist;

    @JsonView(Views.Internal.class)
    private String secret;

    public Album(String id, String title, String artist, String secret) {
        this.id = id;
        this.title = title;
        this.artist = artist;
        this.secret = secret;
    }

}

AlbumController.java

package demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectWriter;

@RestController
public class AlbumController {

    @Autowired
    ObjectMapper mapper;

    @RequestMapping(value = "/album", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    public String getAlbum() throws JsonProcessingException {
        Album foo = new Album("1", "foo", "John Doe", "secretProperty");

        // replace the following value with runtime logic of your choice,
        // e.g. role of a user
        boolean forInternal = false;

        ObjectWriter viewWriter;
        if (forInternal) {
            viewWriter = mapper.writerWithView(Views.Internal.class);
        } else {
            viewWriter = mapper.writerWithView(Views.Public.class);
        }

        return viewWriter.writeValueAsString(foo);
    }
}

So the key is to use jackson's ObjectMapper and ObjectWriter to generate a string of the json representation of your object.

Feels kind of ugly to me, but works. Certainly the question remains how this scales when defining more than one RequestMapping.