Spring JPA-保留@ManyToMany实体-重复的实体错误

如何解决Spring JPA-保留@ManyToMany实体-重复的实体错误

我的用例需要帮助。 我有一个Order实体

@Entity
@Table(name = "orders")
public class Order {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

    @ManyToMany(cascade = {
    CascadeType.PERSIST,CascadeType.MERGE
    })
    @JoinTable(name = "inconsistent_orders",joinColumns = @JoinColumn(name = "order_id"),inverseJoinColumns = @JoinColumn(name = "inconsistency_id")
    )
    private Set<OrderInconsistency> inconsistencies;

    public int getId() {
        return id;
    }

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

    public Set<OrderInconsistency> getInconsistencies() {
        return inconsistencies;
    }

    //getters and setters ommitted for brevity

    public void setInconsistencies(Set<OrderInconsistency> inconsistencies) {
        this.inconsistencies = inconsistencies;
        this.inconsistencies.forEach(i -> i.setOrders(List.of(this)));
    }

    //hashcode and equals ommitted for brevity
}

和一个OrderInconsistency实体

@Entity
@Table(name = "order_inconsistencies")
public class OrderInconsistency {

    @Id
    @Column(name = "id")
    private String id;

    @Basic
    @Column(name = "description")
    private String description;

    @ManyToMany(mappedBy = "inconsistencies")
    private List<Order> orders = new ArrayList<>();

    public OrderInconsistency() {
    }

    public OrderInconsistency(String id,String description) {
        Assert.notNull(id,"El id de la inconsistencia no puede ser null");
        this.id = id.replaceAll(" ","_").toUpperCase();
        this.description = description;
    }

    public String getId() {
        return id;
    }

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

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

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

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        OrderInconsistency that = (OrderInconsistency) o;

        return id.equals(that.id);
    }

    @Override
    public int hashCode() {
        return id.hashCode();
    }
}

我的多对多表格：

CREATE TABLE `inconsistent_orders`
(
    `order_id`         INT(11)     NOT NULL,`inconsistency_id` VARCHAR(25) NOT NULL,PRIMARY KEY (`order_id`,`inconsistency_id`),FOREIGN KEY (`order_id`) REFERENCES `orders` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,FOREIGN KEY (`inconsistency_id`) REFERENCES `order_inconsistencies` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE = InnoDB;

这个想法是Order是这种关系的父级，因此当我保存Order时，它应该保存其不一致之处（如果有）。

订单不一致一旦创建就不会改变。例如，如果保存了一个新的Order并且它的ID为OrderInconsistency的{​​{1}}，并且不存在与该ID不一致的地方，那么JPA应该先创建一个新ID，然后再保存顺序，然后按该顺序将其添加到TOTALS_DONT_MATCH不一致的地方。

将来，其他订单可能会存在这种不一致的情况，并且由于它已经存在于数据库中，因此JPA不应创建它，而只是将其添加到多对多表Set中。

但是，我面临的问题是，即使我手动将一个已经存在的ID分配给手动创建的inconsistent_orders实例，JPA也会尝试插入它，从而导致重复的输入错误

总而言之，我第一次保存订单时，它可以工作并且OrderInconsistency被保存。如果另一个OrderInconsistency被保存并且具有相同的Order，即使它已经存在并且失败，JPA也会尝试插入它。。

例如

OrderInconsistency

我想出的解决方案是拥有一个@Transactional public ValidatedOrderDTO saveConsistentOrder(Order order) { boolean consistentOrder = true; var orderInconsistencies = new HashSet<OrderInconsistency>(); for (OrderValidationService validationService : orderValidationServices) { ValidationResult validationResult = validationService.validate(order); if (!validationResult.isValid()) { // this returns a manually created instance of OrderConsistency with an ID that already exists in the DB OrderInconsistency inconsistency = validationResult.getOrderInconsistency(); orderInconsistencies.add(inconsistency); consistentOrder = false; } } order.setInconsistencies(orderInconsistencies); ordersDAO.save(order); //here,JPA attempts to INSERT the OrderInconsistency even though it already exists in DB return new ValidatedOrderDTO(consistentOrder,consistenciesDescription); } 并手动OrderInconsistencyDAO不一致，如果存在，请将其添加到findById中，如果不存在，则将新实例分配给Order。我不明白为什么这样做有效，以及这样做是否正确。它与托管和非托管实体有关吗？

工作示例-我不明白为什么会这样

Order