@JsonIgnore

• 양방향 연관관계일 경우 무한루프를 방지하기 위해 필드 레벨에서 어노테이션 추가

• Order 엔티티에서 Member 엔티티 다대일 연관관계

@Entity
@Getter @Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED) //생성 메소드만 통일되게 사용하도록 생성자 제한
@Table(name = "orders")
public class Order {

    @Id @GeneratedValue
    @Column(name = "order_id")
    private Long id;

    @ManyToOne(fetch = FetchType.LAZY) //relation owner
    @JoinColumn(name = "member_id")
    private Member member;

    @OneToMany(mappedBy = "order", cascade = CascadeType.ALL) //relation target
    private List<OrderItem> orderItems = new ArrayList<>();

    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL) //relation owner
    @JoinColumn(name = "delivery_id")
    private Delivery delivery;

    private LocalDateTime orderDate;

    @Enumerated(EnumType.STRING) //변경가능성을 고려하여 string으로 지정
    private OrderStatus status; //enum: ORDER, CANCEL

    //==연관관계 편의 메소드==//
    public void setMember(Member member) {
        this.member = member;
        member.getOrders().add(this);
    }

    public void addOrderItem(OrderItem orderItem) {
        orderItems.add(orderItem);
        orderItem.setOrder(this);
    }

    public void setDelivery(Delivery delivery) {
        this.delivery = delivery;
        delivery.setOrder(this);
    }

    //==생성 메소드==//
    public static Order createOrder(Member member, Delivery delivery, OrderItem... orderItems) {
        Order order = new Order();
        order.setMember(member);
        order.setDelivery(delivery);
        for(OrderItem orderItem: orderItems) {
            order.addOrderItem(orderItem);
        }
        order.setStatus(OrderStatus.ORDER);
        order.setOrderDate(LocalDateTime.now());
        return order;
    }

    //==비즈니스 로직==//
    /**
     * 주문 취소
     */
    public void cancel() {
        if (delivery.getStatus() == DeliveryStatus.COMP) {
            throw new IllegalStateException("이미 배송완료된 상품은 취소가 불가능합니다.");
        }
        this.setStatus(OrderStatus.CANCEL);

        //모든 아이템 취소처리
        for(OrderItem orderItem: orderItems) {
            orderItem.cancel();
        }
    }

    //==조회 로직==//
    /**
     * 전체 주문가격 조회
     */
    public int getTotalPrice() {
        int totalPrice = 0;
        for (OrderItem orderItem: orderItems) {
            totalPrice += orderItem.getTotalPrice();
        }
        return totalPrice;
    }

}

• Member엔티티에서는 Order 정보를 또 찾지 않도록 @JsonIgnore 처리

@Entity
@Getter @Setter
public class Member {

    @Id @GeneratedValue
    @Column(name = "member_id")
    private Long id;

    @NotEmpty
    private String name;

    @Embedded //임베디드 내장타입 사용
    private Address address;

    @JsonIgnore
    @OneToMany(mappedBy = "member") //relation target
    private List<Order> orders = new ArrayList<>();
}