@OneToMany獨立實體已傳遞以持久化

Question

在訂單表中插入時會遇到此錯誤

org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: org.vi.entities.LineItem; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: org.vi.entities.LineItem

映射這就是我映射類的方式：

@Entity
public class Order implements Serializable {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name = "id", updatable = false, nullable = false)
    private Long id;
    @Column(name = "delivered", nullable = false)
    private boolean delivered;
    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
    @JoinColumn(name = "fk_order")
    private Set<LineItem> lineItems= new HashSet<LineItem>();
}
@Entity
public class LineItem implements Serializable {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name = "id", updatable = false, nullable = false)
    private Long id;
    @Column(name="quantity", nullable = false)
    private int quantity;
    @ManyToOne
    private Product product;
}
@Entity
public class Product implements Serializable {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name = "id", updatable = false, nullable = false)
    private Long id;    
    @Column(name = "reference", unique = true, nullable = false)
    private String reference;
    @Column(name = "price", nullable = false)
    private double price;
}

在表中插入這是我在表中保存新行的方式

Product p1 = new Product("reference1",10000);
Product p2 = new Product("reference2",20000;
productRepository.save(p1);productRepository.save(p2);

LineItem li1 = new LineItem(6, p1);
LineItem li1 = new LineItem(9, p2);
lineItemRepository.save(li1);lineItemRepository.save(li2);

Set<LineItem> lineItems1= new HashSet<LineItem>();
lineItems1.add(li1);
lineItems1.add(li2);

Order o1 = new Order(false,lineItems1);
orderRepository.save(o1);

如果映射有問題，請您幫我嗎？

Answer 1

請嘗試以下方法：

Order o1 = new Order(false,lineItems1);
o1.getLineItems().add(new LineItem(6, p1););
o1.getLineItems().add(new LineItem(6, p1););
orderRepository.save(o1);

不用創建新的HashSet，而是使用現有的from順序的，因為這是hibernate跟蹤的對象。

Answer 2

我認為您應該嘗試刪除lineItemRepository.save(li1);lineItemRepository.save(li2); 行，因為CascadeType.ALL還將保留Set<LineItem> 。

Answer 3

替換此代碼，

 LineItem li1 = new LineItem(6, p1);
    LineItem li2 = new LineItem(9, p2);
    lineItemRepository.save(li1);lineItemRepository.save(li2);

如果有任何問題，請告知。