[자바 ORM 표준 JPA] JPA 실전 예제 5 - 연관관계 관리

[자바 ORM 표준 JPA] JPA 실전 예제 5 - 연관관계 관리

실전 예제 5 - 연관관계 관리

글로벌 페치 전략 설정#

  • 모든 연관관계를 지연로딩으로
  • @ManyToOne, @OneToOne은 기본이 즉시 로딩이므로 지연로딩으로 변경하길 권장

글로벌 페치 전략 예제소스에 적용#

기존 작성했던 엔티티중 @ManyToOne, @OneToOne에는 (fetch = FetchType.LAZY)를 추가한다.

Album.java

package jpabasic.jpashop.domain;

import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;

@Entity
@DiscriminatorValue("A")
public class Album extends Item{
    private String artist;
    private String etc;

    public String getArtist() {
        return artist;
    }

    public void setArtist(String artist) {
        this.artist = artist;
    }

    public String getEtc() {
        return etc;
    }

    public void setEtc(String etc) {
        this.etc = etc;
    }
}

BaseEntity.java

package jpabasic.jpashop.domain;


import javax.persistence.Column;
import javax.persistence.MappedSuperclass;
import java.time.LocalDateTime;

@MappedSuperclass
public abstract class BaseEntity {
    @Column(name = "REG_ID")
    private String createBy;

    @Column(name = "REG_DT")
    private LocalDateTime createDate;

    @Column(name = "MOD_ID")
    private String LastModifiedBy;

    @Column(name = "MOD_DT")
    private LocalDateTime LastModifiedDate;

    public String getCreateBy() {
        return createBy;
    }

    public void setCreateBy(String createBy) {
        this.createBy = createBy;
    }

    public LocalDateTime getCreateDate() {
        return createDate;
    }

    public void setCreateDate(LocalDateTime createDate) {
        this.createDate = createDate;
    }

    public String getLastModifiedBy() {
        return LastModifiedBy;
    }

    public void setLastModifiedBy(String lastModifiedBy) {
        LastModifiedBy = lastModifiedBy;
    }

    public LocalDateTime getLastModifiedDate() {
        return LastModifiedDate;
    }

    public void setLastModifiedDate(LocalDateTime lastModifiedDate) {
        LastModifiedDate = lastModifiedDate;
    }
}

Book.java

package jpabasic.jpashop.domain;

import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;

@Entity
@DiscriminatorValue("B")
public class Book extends Item{
    private String author;
    private String isbn;

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getIsbn() {
        return isbn;
    }

    public void setIsbn(String isbn) {
        this.isbn = isbn;
    }
}

Category.java - fetch = FetchType.LAZY 적용

package jpabasic.jpashop.domain;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
public class Category extends BaseEntity{

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

    private String name;

    @ManyToOne(fetch = FetchType.LAZY) // **
    @JoinColumn(name = "parent_id")
    private Category parent; // 상위 카테고리

    @OneToMany(mappedBy = "parent")
    private List<Category> child = new ArrayList<>();   // 자식 카테고리

    @ManyToMany
    @JoinTable(name = "CATEGORY_ITEM",
                joinColumns = @JoinColumn(name = "CATEGORY_ID"),
                inverseJoinColumns = @JoinColumn(name ="ITEM_ID")
    )
    private List<Item> items = new ArrayList<>();

    public void setId(Long id) {
        this.id = id;
    }

    public Long getId() {
        return id;
    }
}

Delivery.java - fetch = FetchType.LAZY 적용

package jpabasic.jpashop.domain;

import javax.persistence.*;

@Entity
public class Delivery extends BaseEntity{

    @Id @GeneratedValue
    @Column(name = "DELIVERY_ID")
    private Long id;
    private String city;
    private String street;
    private String zipcode;

    @Enumerated(EnumType.STRING)
    private DeliveryStatus status;


    @OneToOne(mappedBy = "delivery" , fetch = FetchType.LAZY) // **
    private Order order;


    public void setId(Long id) {
        this.id = id;
    }

    public Long getId() {
        return id;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getZipcode() {
        return zipcode;
    }

    public void setZipcode(String zipcode) {
        this.zipcode = zipcode;
    }

    public DeliveryStatus getStatus() {
        return status;
    }

    public void setStatus(DeliveryStatus status) {
        this.status = status;
    }

    public Order getOrder() {
        return order;
    }

    public void setOrder(Order order) {
        this.order = order;
    }
}

DeliveryStatus.java

package jpabasic.jpashop.domain;

public enum DeliveryStatus {
    ORDER, CANCEL
}

Item.java

package jpabasic.jpashop.domain;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn
public abstract class Item extends BaseEntity{
    public Item(){
    }

    public Item(String name, int price, int stockQuantity) {
        this.name = name;
        this.price = price;
        this.stockQuantity = stockQuantity;
    }

    @Id @GeneratedValue
    @Column(name="ITEM_ID")
    private Long id;
    private String name;
    private int price;
    private int stockQuantity;

    @ManyToMany(mappedBy = "items")
    private List<Category> categories = new ArrayList<>();

    public Long getId() {
        return id;
    }


    public void setId(Long id) {
        this.id = id;
    }


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public int getStockQuantity() {
        return stockQuantity;
    }

    public void setStockQuantity(int stockQuantity) {
        this.stockQuantity = stockQuantity;
    }
}

Member.java

package jpabasic.jpashop.domain;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
public class Member extends BaseEntity{

    public Member(){}

    @Id @GeneratedValue
    @Column(name="MEMBER_ID")
    private Long id;
    private String name;
    private String cicy;
    private String street;
    private String zipcode;

    @OneToMany(mappedBy = "member")
    private List<Order> orders = new ArrayList<>(); //관례상 초기 값을 두어 NullPointer Exception을 방지

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCicy() {
        return cicy;
    }

    public void setCicy(String cicy) {
        this.cicy = cicy;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getZipcode() {
        return zipcode;
    }

    public void setZipcode(String zipcode) {
        this.zipcode = zipcode;
    }

    public List<Order> getOrders() {
        return orders;
    }

    public void setOrders(List<Order> orders) {
        this.orders = orders;
    }
}

Movie.java

package jpabasic.jpashop.domain;

import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;

@Entity
@DiscriminatorValue("M")
public class Movie extends Item{
    private String director;
    private String actor;

    public String getDirector() {
        return director;
    }

    public void setDirector(String director) {
        this.director = director;
    }

    public String getActor() {
        return actor;
    }

    public void setActor(String actor) {
        this.actor = actor;
    }
}

Order.java - fetch = FetchType.LAZY 적용

package jpabasic.jpashop.domain;

import javax.persistence.*;
import jpabasic.jpashop.domain.Member;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

@Entity
@Table(name = "ORDERS") // DB에 따라 ORDER가 예약어일 경우가 있어 ORDERS
public class Order extends BaseEntity{

    public Order(){}

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

    private LocalDateTime orderDate;

    @Enumerated(EnumType.STRING)
    private OrderStatus status;

    @ManyToOne(fetch = FetchType.LAZY) // **
    private Member member;

    @OneToMany(mappedBy = "order")
    private List<OrderItem> orderItems = new ArrayList<>(); //관례상 초기 값을 두어 NullPointer Exception을 방지

    @OneToOne(fetch = FetchType.LAZY) // **
    @JoinColumn(name = "DELIVERY_ID")
    private Delivery delivery;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public LocalDateTime getOrderDate() {
        return orderDate;
    }

    public void setOrderDate(LocalDateTime orderDate) {
        this.orderDate = orderDate;
    }

    public OrderStatus getStatus() {
        return status;
    }

    public void setStatus(OrderStatus status) {
        this.status = status;
    }

    public Member getMember() {
        return member;
    }

    public void setMember(Member member) {
        this.member = member;
    }

    public List<OrderItem> getOrderItems() {
        return orderItems;
    }

    public void setOrderItems(List<OrderItem> orderItems) {
        this.orderItems = orderItems;
    }

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

    public void addMember(Member member) {
        this.member = member;
        member.getOrders().add(this);
    }
}

OrderItem.java - fetch = FetchType.LAZY 적용

package jpabasic.jpashop.domain;

import javax.persistence.*;
import java.util.List;

@Entity
public class OrderItem extends BaseEntity{
    public OrderItem(){
    }

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

    private int orderPrice;

    private int count;

    @ManyToOne(fetch = FetchType.LAZY) // **
    private Order order;

    @ManyToOne(fetch = FetchType.LAZY) // **
    private Item item;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public int getOrderPrice() {
        return orderPrice;
    }

    public void setOrderPrice(int orderPrice) {
        this.orderPrice = orderPrice;
    }

    public int getCount() {
        return count;
    }

    public void setCount(int count) {
        this.count = count;
    }

    public Order getOrder() {
        return order;
    }

    public void setOrder(Order order) {
        this.order = order;
    }

    public Item getItem() {
        return item;
    }

    public void setItem(Item item) {
        this.item = item;
    }
}

OrderStatus.java

package jpabasic.jpashop.domain;

public enum OrderStatus {
    ORDER, CANCEL
}

JpaMain.java - 애플리케이션 재시작

package jpabasic.jpashop;

import jpabasic.jpashop.domain.*;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;

public class JpaMain {
    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("jpashop");
        EntityManager em = emf.createEntityManager();
        EntityTransaction tx = em.getTransaction();

        tx.begin();

        try{
            Book book = new Book();
            book.setName("JPA");
            book.setAuthor("김영한");
            em.persist(book);

            tx.commit();

        }catch (Exception e){
            e.printStackTrace();
            tx.rollback();
        }finally {
            em.close();
        }
        emf.close();

    }
}

영속성 전이 설정#

주문(Order)을 생성할 당시 배송정보(Delivery), 그리고 주문상품(OrderItem)을 같이 생성한다는 뜻

  • Order -> Delivery를 영속성 전이 ALL 설정
  • Order -> OrderItem을 영속성 전이 ALL 설정
package jpabasic.jpashop.domain;

import javax.persistence.*;
import jpabasic.jpashop.domain.Member;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

@Entity
@Table(name = "ORDERS") // DB에 따라 ORDER가 예약어일 경우가 있어 ORDERS
public class Order extends BaseEntity{

    public Order(){}

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

    private LocalDateTime orderDate;

    @Enumerated(EnumType.STRING)
    private OrderStatus status;

    @ManyToOne(fetch = FetchType.LAZY)
    private Member member;

    @OneToMany(mappedBy = "order", cascade = CascadeType.ALL) // **
    private List<OrderItem> orderItems = new ArrayList<>(); //관례상 초기 값을 두어 NullPointer Exception을 방지

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

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public LocalDateTime getOrderDate() {
        return orderDate;
    }

    public void setOrderDate(LocalDateTime orderDate) {
        this.orderDate = orderDate;
    }

    public OrderStatus getStatus() {
        return status;
    }

    public void setStatus(OrderStatus status) {
        this.status = status;
    }

    public Member getMember() {
        return member;
    }

    public void setMember(Member member) {
        this.member = member;
    }

    public List<OrderItem> getOrderItems() {
        return orderItems;
    }

    public void setOrderItems(List<OrderItem> orderItems) {
        this.orderItems = orderItems;
    }

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

    public void addMember(Member member) {
        this.member = member;
        member.getOrders().add(this);
    }
}

설계시 Delivery의 라이프 사이클을 따로 관리 해야하는 것도 고민을 해볼 필요가 있습니다. 복잡성이나, 비즈니스 상황에 따라 Cascade를 적용할지 뺄지 정해야 합니다.

contact

참고- 자바 ORM 표준 JPA - 김영한#

[자바 ORM 표준 JPA] JPA 실전 예제 5 - 연관관계 관리