N : M 양방향 관계에서 중간 테이블 직접 생성

N : M 양방향 관계에서 중간 테이블 직접 생성하면 된다.

 

Order.java 를 [entity] 내에 생성한다.

package com.sparta.jpaadvance.entity;

import jakarta.persistence.*;
import lombok.Getter;
import lombok.Setter;

@Entity
@Getter
@Setter
@Table(name = "orders")
public class Order {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne
    @JoinColumn(name = "food_id")
    private Food food;

    @ManyToOne
    @JoinColumn(name = "user_id")
    private User user;
}

package com.sparta.jpaadvance.repository;

import com.sparta.jpaadvance.entity.Order;
import org.springframework.data.jpa.repository.JpaRepository;

public interface OrderRepository extends JpaRepository<Order,Long> {
}

package com.sparta.jpaadvance.entity;

import jakarta.persistence.*;
import lombok.Getter;
import lombok.Setter;

import java.util.ArrayList;
import java.util.List;

@Entity
@Getter
@Setter
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;

    @OneToMany(mappedBy = "user")
    private List<Order> orderList = new ArrayList<>();
}

package com.sparta.jpaadvance.entity;

import jakarta.persistence.*;
import lombok.Getter;
import lombok.Setter;

import java.util.ArrayList;
import java.util.List;

@Entity
@Getter
@Setter
@Table(name = "food")
public class Food {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private double price;

    @OneToMany(mappedBy = "food")
    private List<Order> orderList = new ArrayList<>();
}

 

Test Code : 

package com.sparta.jpaadvance.relation;

import com.sparta.jpaadvance.entity.Food;
import com.sparta.jpaadvance.entity.Order;
import com.sparta.jpaadvance.entity.User;
import com.sparta.jpaadvance.repository.FoodRepository;
import com.sparta.jpaadvance.repository.OrderRepository;
import com.sparta.jpaadvance.repository.UserRepository;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.annotation.Rollback;
import org.springframework.transaction.annotation.Transactional;

@Transactional
@SpringBootTest
public class OrderTest {

    @Autowired
    UserRepository userRepository;
    @Autowired
    FoodRepository foodRepository;
    @Autowired
    OrderRepository orderRepository;
    @Test
    @Rollback(value = false)
    @DisplayName("중간 테이블 Order Entity 테스트")
    void test1() {

        User user = new User();
        user.setName("Robbie");

        Food food = new Food();
        food.setName("후라이드 치킨");
        food.setPrice(15000);

        // 주문 저장
        Order order = new Order();
        order.setUser(user); // 외래 키(연관 관계) 설정
        order.setFood(food); // 외래 키(연관 관계) 설정

        userRepository.save(user);
        foodRepository.save(food);
        orderRepository.save(order);
    }

    @Test
    @DisplayName("중간 테이블 Order Entity 조회")
    void test2() {
        // 1번 주문 조회
        Order order = orderRepository.findById(1L).orElseThrow(NullPointerException::new);

        // order 객체를 사용하여 고객 정보 조회
        User user = order.getUser();
        System.out.println("user.getName() = " + user.getName());

        // order 객체를 사용하여 음식 정보 조회
        Food food = order.getFood();
        System.out.println("food.getName() = " + food.getName());
        System.out.println("food.getPrice() = " + food.getPrice());
    }

}

 

 

 

주문일 추가하기 :

package com.sparta.jpaadvance.entity;

import jakarta.persistence.*;
import lombok.Getter;
import lombok.Setter;
import org.springframework.data.annotation.CreatedDate;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;

import java.time.LocalDateTime;

@Entity
@Getter
@Setter
@Table(name = "orders")
@EntityListeners(AuditingEntityListener.class)
public class Order {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne
    @JoinColumn(name = "food_id")
    private Food food;

    @ManyToOne
    @JoinColumn(name = "user_id")
    private User user;

    @CreatedDate
    @Temporal(TemporalType.TIMESTAMP)
    private LocalDateTime orderDate;
}

 

 

    @CreatedDate
    @Temporal(TemporalType.TIMESTAMP)
    private LocalDateTime orderDate;

클래스 내부에 해당 칼럼을 추가한다.

 

@EntityListeners(AuditingEntityListener.class)

클래스 위에 해당 어노테이션을 기재하여야 JPA auditing 기능을 실행할 수 있다.

 

 

또한, Application.java 파일에 

아래와 같이 @EnableJpaAuditing 을 기재하여야 한다.

package com.sparta.jpaadvance;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;

@EnableJpaAuditing
@SpringBootApplication
public class JpaAdvanceApplication {

    public static void main(String[] args) {
        SpringApplication.run(JpaAdvanceApplication.class, args);
    }

}