How to return ID of Db saved JSON in Spring

Question

I am building a sample app for JSON tutorial. After posting JSON object (description and date), an ID should be auto generated in the database. How can I get this ID as the only field in the JSON response?

    @JsonView(View.Summary.class)
    @PostMapping(path = "/api/object/new")
    public Object AddObjectApi(@RequestBody Map<String, String> object) {

        Object newObject = new Object(
            object.get("description"),
            LocalDateTime.now().truncatedTo(ChronoUnit.SECONDS));

        Object savedObject = repository.save(newObject);
        savedCObject.getId();

        return savedObject;
    }

Sample input (Post JSON):

{
   "description" : "This is object description"
}

Sample Output (Returned JSON response):

{
   "id" : "1"
}

Answer 1

You can create a new class which has a field called id

public class ResponseData{
   public Integer id;
   
   public ResponseData(){
   
   }

   public ResponseData(Integer id){
     this.id = id;
   }
}

Then after saving your object in db you can return the response like this

    @PostMapping(path = "/api/object/new")
    public ResponseData AddObjectApi(@RequestBody Map<String, String> object) {

        Object newObject = new Object(
            object.get("description"),
            LocalDateTime.now().truncatedTo(ChronoUnit.SECONDS));

        Object savedObject = repository.save(newObject);
        
        ResponseData responseData = new ResponseData(savedObject.getId());
        return responseData;
    }