java.lang.IllegalStateException:具有@ManyToMany 3实体的同一实体的多个表示形式

Question

我有3个具有ManyToMany关系的实体,如下所示:

角色实体:

@Entity
public class Role {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer roleID;
    private String roleName;
    private String description;

    @ManyToMany(cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH}, fetch = FetchType.EAGER)
    @JoinTable(name = "role_permission", joinColumns = {@JoinColumn(name = "role_id")}, inverseJoinColumns = {@JoinColumn(name = "permission_id")})
    private Set<Permission> permissions = new LinkedHashSet<Permission>();
}

许可实体:

@Entity
public class Permission {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int permissionID;
    private String permissionName;
    private String description;

    @ManyToMany(cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH}, fetch = FetchType.EAGER)
    @JoinTable(name = "permission_functionality", joinColumns = {@JoinColumn(name = "permission_id")}, inverseJoinColumns = {@JoinColumn(name = "functionality_id")})
    private Set<Functionality> functionalities = new LinkedHashSet<>();
}

功能实体:

@Entity
public class Functionality {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String name;
}

我做了以下事情:

1. 我创建了3个功能.

   Functionality1, Functionality2, Functionality3
   

2. 然后创建2个权限:

   Permission1 with Functionality1, Functionality2
   
   Permission2 with Functionality2, Functionality3
   

3. 然后在创建角色时:

   Role1 with Permission1 and Permission2 
   

   java.lang.IllegalStateException:正在合并同一实体[com.persistence.entity.admin.Functionality#1]的多个表示.分离:[com.persistence.entity.admin.Functionality@4729256a]; 分离:[com.persistence.entity.admin.Functionality@56ed25db]

Answer 1

通过删除Permission实体上的CascadeType.MERGE来修复它

Answer 2

正确的解决方案是升级到hibernate 4.2.15/4.3.6或更高版本,并将以下行添加到persistence.xml:

<property name="hibernate.event.merge.entity_copy_observer" value="allow"/>

Answer 3

就像其他人的答案基于HHH-9106 一样，但是，因为我使用的是带有基于 Java 的注释的 Spring Boot，所以我不得不在以下内容中使用application.properties：

spring.jpa.properties.hibernate.event.merge.entity_copy_observer=allow

Answer 4

检查你的equals和hashCode方法,确保它是一致的并且正确定义.例如,我在计算hashCode时复制并错误地粘贴了另一个类,这导致对象永远不会与自身相等:(.

Answer 5

我也遇到了同样的问题，并通过在application.yaml文件中添加一些配置来解决了这个问题。

  jpa:
    properties:
      hibernate:
        enable_lazy_load_no_trans: true
        event:
          merge:
            entity_copy_observer: allow

在这里看到它如何使用spring-boot和JPA持久化包含另一个未持久实体的多个相同实例的新实体？

Answer 6

我可以通过更换来修复它

cascade = CascadeType.All

和

casecade={CascadeType.PERSIST,CascadeType.REMOVE}