sebCarabali · June 16, 2022 02:49
diff --git a/Hibernate Create Update Delete a List of child objects at once.java b/Hibernate Create Update Delete a List of child objects at once.java
    @Entity
    public class Parent implements Serializable {
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
        private Long id;

        @OneToMany(mappedBy = "parent", cascade = CascadeType.ALL, orphanRemoval = true)
        private Set<Child> children = new HashSet<>();

        ...
    }


    @Entity
    public class Child implements Serializable {
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
        private Long id;

        @ManyToOne
        @JoinColumn(name = "parent_id")
        private Parent parent;

        ...
    }
 
 void processChildDto(Parent parent, Set<ChildDto> childDtos) {
        Set<Child> children = new HashSet<>();

        for (ChildDto dto : childDtos) {
            Child child;
            if (dto.getId() == null) {
                //CREATE MODE: create new child
                child = new Child();
                child.setParent(parent); //associate parent 
            } else {
                //UPDATE MODE : fetch by id
                child = childRepository.getOne(dto.getId());
            }

            BeanUtils.copyProperties(dto, child);//copy properties from dto

            children.add(child);
        }
        parent.getChildren().clear();
        parent.getChildren().addAll(children);

        //finally save the parent ( and children)
        parentRepository.save(parent);
    }