JSONObject always returns "empty": false

Question

There is a Spring Rest Controller :

@RestController
@RequestMapping("secanalytique")
public class SectionAnalytiqueController {

    @GetMapping(value = "/sectionbyaxepro/{codecomp}", produces = "application/json")
    public JSONObject getByAxePro(@PathVariable String codecomp) {
        JSONObject jsonModel = new JSONObject();
        jsonModel.put("cce0","frityyy");
        return jsonModel;
    }

}

I made a test with Postman : http://172.20.40.4:8080/Oxalys_WS/secanalytique/sectionbyaxepro/8 ; and what I got is always

{
    "empty": false
}

So what is wrong ?

Answer 1

I met same issue, and found the way to handle.

@GetMapping(value = "/test/{id}", produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<Object> getById(@PathVariable String id) {
    JSONObject jsObj = new JSONObject();
    jsObj.put("t0","test0");
    JSONArray jsArr = new JSONArray();
    jsArr.put(jsObj.toMap());

    return new ResponseEntity<>(jsObj.toMap(), HttpStatus.OK);
    //return new ResponseEntity<>(jsArr.toList(), HttpStatus.OK);
}

Answer 2

There was one issue with your implementation that you are creating JSON object explicitly and returning it which is not required.
Instead, you should just send your java POJO/class, spring will convert it to JSON and return it.
Spring uses Jackson as the default serializer/deserializer.
Here since an object is already JSONObject, Jackson does not know how to serialize it.

There are two ways to solve this problem:

solution 1.
Define your own data type and populate it.

import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;

@GetMapping(value = "/sectionbyaxepro/{codecomp}", produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<Map<String, String>> getByAxePro(@PathVariable String codecomp) {
    Map<String, String> map = new HashMap<>();
    map.put("cce0","frityyy");
    return ResponseEntity.status(HttpStatus.OK).body(map);
}

OR

Solution 2.

Modify your existing code to either of the following ways.

1

import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;

@GetMapping(value = "/sectionbyaxepro/{codecomp}", produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<String> getByAxePro(@PathVariable String codecomp) {
    JSONObject jsonModel = new JSONObject();
    jsonModel.put("cce0","frityyy");
    return ResponseEntity.status(HttpStatus.OK).body(jsonModel.toString());
}

2

@GetMapping(value = "/sectionbyaxepro/{codecomp}", produces = MediaType.APPLICATION_JSON_VALUE)
public String getByAxePro(@PathVariable String codecomp) {
   JSONObject jsonModel = new JSONObject();
   jsonModel.put("cce0","frityyy");
   return jsonModel.toString();
}