Producing and consuming custom JSON Objects in Spring RESTful services

Question

I have some JSON Objects that are more complex than the JSON representations of the java objects I have. I have methods that build these JSON Objects and I would like to return and consume these directly. I use org.json library to build my JSONs. I could get the GET method working by returning the JSON Object as a String. Is this the correct way to go about it?

@RequestMapping(value = "/getjson", method = RequestMethod.GET, produces="application/json")
@ResponseBody
public String getJson() {
    JSONObject json = new JSONObject();
     JSONObject subJson = new JSONObject();
    subJson .put("key", "value");
    json.put("key", subJson);
    return json.toString();
}

Now I want to know how do I consume a JSON Object? As a string and convert it to a JSON Object?

    @RequestMapping(value = "/post", method = RequestMethod.POST, produces="application/json", consumes="application/json")
    @ResponseBody
    public String post(@RequestBody String json) {
        JSONObject obj = new JSONObject(json);
        //do some things with json, put some header information in json
        return obj.toString();
    }

Is this the correct way to go about my problem? I am a novice, so kindly point out anything that can be done better. Please note: I do not want to return POJOs.

Solution 1

I think using jackson library you can do something like below.

@RequestMapping(value = "/getjson", method = RequestMethod.GET, produces="application/json")
@ResponseBody
public String getJson() {
   //your logic
    ObjectMapper mapper = new ObjectMapper();
    return mapper.writeValueAsString(json);
}

@RequestMapping(value = "/post", method = RequestMethod.POST, produces="application/json", consumes="application/json")
@ResponseBody
public String post(@RequestBody String json) {
    POJO pj = new POJO();
    ObjectMapper mapper = new ObjectMapper();
    pj = mapper.readValue(json, POJO.class);

    //do some things with json, put some header information in json
    return mapper.writeValueAsString(pj);
}

Solution 2

I much rather the alternative to use Jackson with Spring mvc since you dont have to worry of the serialization and deserialization of your objects/json-json/object. But if you still want to the process I like to use gson of google.

http://www.javacreed.com/simple-gson-example/

Solution 3

You can use jackson lib, jackson allows convert to/from json using spring mvc.

1. Spring configure @ResponseBody JSON format
2. Jackson 2.0 with Spring 3.1