Spring Data REST-当PATCH在请求体中带有空数组时出现异常

Question

@Entity
@Data
public class Atoll {

    @Id
    @GeneratedValue
    private Long id;

    private String atollName;

    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
    @JoinColumn(name = "atoll_id")
    private List<Island> islands = new ArrayList<>();

}

@Entity
@Getter
@Setter
public class Island extends Auditable{

    @Id
    @GeneratedValue
    private Long id;

    private String islandName;

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        Island that = (Island) o;
        return Objects.equals(this.getCreatedDate(), that.getCreatedDate());

    }

    @Override
    public int hashCode() {
        return Objects.hash(this.getCreatedDate());
    }

}

{
    "atollName":"Haa Alif",
    "islands":[{
        "islandName":"Dhidhdhoo"
    }]
}

A collection with cascade=\"all-delete-orphan\" was no longer referenced by the owning entity instance: com.boot.demo.model.Atoll.islands; nested exception is org.hibernate.HibernateException: A collection with cascade=\"all-delete-orphan\" was no longer referenced by the owning entity instance: com.boot.demo.model.Atoll.island

我搜索了stackoverflow并找到了这个答案，它说这主要是由于equals和hashCode方法造成的，所以我重写了默认的equals和hashCode方法，但错误仍然是一样的(equals方法中使用的createddate是auditable类的一部分）。

那么是什么导致了这个异常，我如何修复它呢？

Answer 1

您必须在Atoll类中实现add/remove方法。

所以，你的映射：

@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name = "atoll_id")
private List<Island> islands = new ArrayList<>();

和两个添加/删除方法：

public void addIsland(Island island) {
    this.getIslands().add(island);
}

public void removeIsland (Island island) {
    this.getIslands().remove(island);
}