[Spring] Embedded, Join Column의 변수에 접근하기

Domain

WishList Entity

import jakarta.persistence.Column;
import jakarta.persistence.Embedded;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.Table;
import jakarta.persistence.UniqueConstraint;

@Entity
@Table(name = "wish_products", uniqueConstraints = {@UniqueConstraint(columnNames = {"user_id", "product_id"})})
public class WishList {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long wishListId;

    @Embedded
    private UserProduct userProduct;

    @Column(nullable = false)
    private int quantity;

    protected WishList() {
    }

    public WishList(UserProduct userProduct, int quantity) {
        this.wishListId = null;
        this.userProduct = userProduct;
        this.quantity = quantity;
    }
    
    // getter setter 생략
}

UserProduct 객체 (embeddable)

import gift.product.entity.Product;
import jakarta.persistence.Embeddable;
import jakarta.persistence.JoinColumn;
import jakarta.persistence.ManyToOne;

@Embeddable
public class UserProduct {
    private Long userId;

    @ManyToOne
    @JoinColumn(name = "product_id")
    private Product product;

    protected UserProduct() {
    }

    public UserProduct(Long userId, Product product) {
        this.userId = userId;
        this.product = product;
    }
    
    // getter, setter 생략
}

Product Entity (Join Column)

import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.Table;

@Entity
@Table(name = "products")
public class Product {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long productId;

    @Column(nullable = false)
    private String name;

    @Column(nullable = false)
    private int price;

    @Column(nullable = false)
    private String image;

    protected Product() {
    }

    public Product(String name, int price, String image) {
        this.productId = null;
        this.name = name;
        this.price = price;
        this.image = image;
    }

    // getter, setter 생략
}

 

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접근 방법

Sort property

// userProduct 객체의 product 객체의 price 변수에 접근
String sortProperty = "userProduct_product_price";
Direction direction = Direction.fromString("ASC");

Sort sort = Sort.by(direction, sortProperty);

 

JPA 쿼리 자동 생성

// userProduct라는 객체 내부의 userId라는 변수에 접근
Page<WishList> findByUserProductUserId(Long userId, Pageable pageable);

 

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결론

위의 두 예제 말고도 접근할 방법은 더 많을 수도 있겠습니다.

Table의 column 이름이 아닌 객체 이름을 기준으로 접근하면 "이게 되네"라는 느낌으로 성공할 수 있을 겁니다.