2个外键从不同实体进入新表休眠

您需要一个关联表，通常出于各种原因通常在JPA中构建该关联表，主要是为了控制表中的内容，或者在这种情况下映射n路M：N关系。

创建所有实体：

@Entitypublic class User {    @Id @GeneratedValue(strategy=GenerationType.AUTO)     private Integer id;    private String userName;    @oneToMany(mappedBy="user")    private Set<UserDepartmentRoleAssociation> associations;... etc}

和

@Entitypublic class Department {    @Id @GeneratedValue(strategy=GenerationType.AUTO)     private Integer id;    private String department;    @oneToMany(mappedBy="department")    private Set<UserDepartmentRoleAssociation> associations;    ... etc}

和

@Entitypublic class Role {    @Id @GeneratedValue(strategy=GenerationType.AUTO)     private Integer id;    private String role;    ... etc}

并创建关联表和ID类。

@Entitypublic class UserDepartmentRoleAssociation {    @EmbeddedId private UserDepartmentRoleAssociationId id;    @ManyToOne @MapsId("userId")    private User user;    @ManyToOne @MapsId("departmentId")    private Department department;    @ManyToOne @MapsId("roleId")    private Role role;    public UserDepartmentRoleAssociation() {        id = new UserDepartmentRoleAssociationId();    }    ... etc}

和

@Embeddablepublic class UserDepartmentRoleAssociationId implements Serializable {    private Integer userId;    private Integer departmentId;    private Integer roleId;    ... etc}

并保持一段感情然后…

        User user = new User();        user.setUserName("user1");        Department department = new Department();        department.setDepartment("department 1");        Role role = new Role();        role.setRole("Manager");        UserDepartmentRoleAssociation association = new UserDepartmentRoleAssociation();        association.setUser(user);        association.setDepartment(department);        association.setRole(role);        em.persist(user);        em.persist(department);        em.persist(role);        em.persist(association);

并通过join fetch读取它

User user = em.createQuery("select u from User u left join fetch u.associations ass left join fetch ass.department left join fetch ass.role where u.id = :id", User.class).setParameter("id", 1).getSingleResult();

请注意，在这些情况下，我使用了in

Set

List

Department

User

associations

UserDepartmentRoleAssociation

associations