[FIXED] Return only specific fields of model from api in spring boot

Issue

I am writing a spring boot api which fetches some data from db, store in model object & returns it. But I want to return only few fields of the model as api response.

List<MyModel> myModelList = new ArrayList<>();
mongoUserCollection.find().into(myModelList);



 class MyModel{
    public int id; 
    public String name;
    public String lastname;
    public int age;
// getter & setter of all properties
    }

I am showing myModelList as response. In response its showing all the fields. How to show only specific fields like id and age only. Selecting only id & age from db will still show all fields of model in response (name & lastname will be shown as null). Is there any way apart from creating new ModelView class or setting JsonIgnore as this model?

Solution

If the model which you are returning is going to be specific to single API go with @JsonIgnore, the below example will ignore the id in the response

class MyModel{
    @JsonIgnore
    public int id; 
    public String name;
    public String lastname;
    public int age;
}

But let say the same model is going to be used for different API and each API has different type of result then I would highly recommend @JsonView to handle those. A simple example will be below (will consider MyModel from your question)

Create a class Views.java with an empty interface

public class Views {
    public interface MyResponseViews {};
}

In Model

class MyModel{
  public int id; 
  @JsonView(Views.MyResponseViews.class)
  public String name;
  @JsonView(Views.MyResponseViews.class)
  public String lastname;
  public int age;
}

Last thing you have to add to the controller that send this response (Assuming your controller here)

MyModelController.java

class MyModelController {
   // Autowiring MyModelService ...

   
   @GetMapping("/get")
   @JsonView(Views.MyResponseViews.class)
   public ResponseEntity get() {
     // Your logic to return the result
   }

}

The above will return only name and lastname Refer this for more detail this

Answered By - Avi