JPA - Only get parent, not children

Question

I have a parent like this:

@Entity
@Table(name="parent")
public class Parent {

    private List<Child> childs;
    private List<AnotherChild> anotherChilds;

    @OneToMany(mappedBy = "parent", fetch = FetchType.LAZY)
    public List<Child> getChilds() {
        return childs;
    }

    @OneToMany(mappedBy = "parent", fetch = FetchType.LAZY)
    public List<AnotherChild> getAntoherChilds() {
        return anotherChilds;
    }

    //Getters and Setters ommited
}

And two children like this

@Entity
@Table(name="child")
public class Child {

    private Parent parent;

    @ManyToOne
    @JoinColumn(name = "column_name")
    public Parent getParent() {
        return patern;
    }
}

@Entity
@Table(name="another_child")
public class AnotherChild {

    private Parent parent;

    @ManyToOne
    @JoinColumn(name = "column_name")
    public Parent getParent() {
        return patern;
    }
}

I have a named query which gets all the Parents, but this is also loading all the children? How can I stop the children for automatically loading?

Thanks.

@AbdullahWasi it is just the standard findAll query, and is being called form JAX-RS as a named query — iqueqiorio, Dec 15 '16 at 04:05
Lazy loading is the default so if they are being loaded then it is your code that it is doing it - so post the relevant code. — Alan Hay, Dec 15 '16 at 09:18
Did you find any solution for this fetching parent without children? — Aadam, Sep 12 '19 at 22:01

score 4 · Answer 1 · answered Apr 30 '20 at 10:05

I know my answer is late, but it may help others because I had the same problem for a while, based this answer if you use rest API, Spring calls Jackson to return Parent object and Jackson calls getChild, for this reason, parent's child loaded. one solution is to define a Dto class for the Parent class that does not include Child, for example

public class ParentResponseDto{
    private Long id
    private String name; 
    //and your desired attribute that you want to load
}

then in rest controller return ParenResponseDto

@GetMapping
public ParenResponseDto getParent(Long id){
    Parent p = repository.findById(id);
    ParenResponseDto dto = mapParentToParenResponseDto();
    return dto;
}

you can use ModelMapper to map classes, this is a great module

**MapStruct** is also very efficient, check this answer that prevent the same problem : https://stackoverflow.com/a/65391112/2641426 — DependencyHell, Dec 21 '20 at 10:31

JPA - Only get parent, not children

1 Answers1