使用 JPA 和 Spring 注解映射购物车-购物车项-商品实体关系

@Entity
@Table(name="my_cart")
public class Cart {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="cart_id")
    private Long cartId;

    @OneToMany(mappedBy = "cart", cascade = CascadeType.ALL, orphanRemoval = true)
    private List<CartItem> cartItems;

    @Column(name="cart_total_number_of_items")
    private long totalNumberOfItems;

    @Column(name="cart_total_price")
    private double totalPrice;

    // Getters and setters and constructor
    public Cart(){}

    public Long getCartId() {
        return cartId;
    }

    public void setCartId(Long cartId) {
        this.cartId = cartId;
    }

    public List<CartItem> getCartItems() {
        return cartItems;
    }

    public void setCartItems(List<CartItem> cartItems) {
        this.cartItems = cartItems;
    }

    public long getTotalNumberOfItems() {
        return totalNumberOfItems;
    }

    public void setTotalNumberOfItems(long totalNumberOfItems) {
        this.totalNumberOfItems = totalNumberOfItems;
    }

    public double getTotalPrice() {
        return totalPrice;
    }

    public void setTotalPrice(double totalPrice) {
        this.totalPrice = totalPrice;
    }
}

@Entity
@Table(name="cart_items")
public class CartItem {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="cartitem_id")
    private Long cartItemId;

    @Column(name="cart_item_name")
    private String productName;

    @Column(name="cart_item_description")
    private String itemDescription;

    @Column(name="cart_item_quantity")
    private int itemQuantity;

    @Column(name="cart_item_price")
    private double itemPrice;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "cart_id")
    private Cart cart;

    @OneToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "item_id")
    private Item item;

    public CartItem(){}

    public Long getCartItemId() {
        return cartItemId;
    }

    public void setCartItemId(Long cartItemId) {
        this.cartItemId = cartItemId;
    }

    public String getProductName() {
        return productName;
    }

    public void setProductName(String productName) {
        this.productName = productName;
    }

    public String getItemDescription() {
        return itemDescription;
    }

    public void setItemDescription(String itemDescription) {
        this.itemDescription = itemDescription;
    }

    public int getItemQuantity() {
        return itemQuantity;
    }

    public void setItemQuantity(int itemQuantity) {
        this.itemQuantity = itemQuantity;
    }

    public double getItemPrice() {
        return itemPrice;
    }

    public void setItemPrice(double itemPrice) {
        this.itemPrice = itemPrice;
    }

    public Cart getCart() {
        return cart;
    }

    public void setCart(Cart cart) {
        this.cart = cart;
    }

    public Item getItem() {
        return item;
    }

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

@Entity
@Table(name="my_items")
public class Item {

    @Id
    @Column(name="item_id")
    private String itemId;

    @Column(name="item_name", nullable = false)
    private String name;

    @Column(name="item_description", nullable = false)
    private String description;

    @Column(name="item_price", nullable = false)
    private Double price;

    public Item(){}

    public String getItemId() {
        return itemId;
    }

    public void setItemId(String itemId) {
        this.itemId = itemId;
    }

    public String getName() {
        return name;
    }

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

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Double getPrice() {
        return price;
    }

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