Question

@MappedSuperclass
public abstract class IdEntity /*extends AbstractPersistable<Integer>*/
        implements Serializable,Cloneable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    protected Integer id;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.setId(id);
    }
}


    @Entity
@Table(name = "user")
//@AttributeOverride( name="id", column = @Column(name="id") )
public class User extends IdEntity{

    @ManyToMany
    @JoinTable(name = "user_role",
            joinColumns = @JoinColumn(name = "user_id"),
            inverseJoinColumns = @JoinColumn(name = "role_id", referencedColumnName = "id"))
    public Set<Role> getRoles() {
        return roles;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }

}


@Entity
@Table(name = "role")
//@AttributeOverride( name="id", column = @Column(name="id") )
public class Role extends IdEntity {

    private Set<User> users = new HashSet<User>();

    @ManyToMany(mappedBy = "roles")
    public Set<User> getUsers() {
        return users;
    }

    public void setUsers(Set<User> users) {
        this.users = users;
    }

}

堆栈追踪：

Caused by: javax.persistence.PersistenceException: [PersistenceUnit: com.rootls] Unable to build EntityManagerFactory
    at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:915)
    at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:890)
    at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:74)
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:286)
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:310)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1545)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1483)
    ... 50 more
Caused by: org.hibernate.MappingException: Could not determine type for: java.util.Set, at table: user, for columns: [org.hibernate.mapping.Column(roles)]
    at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:305)
    at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:289)
    at org.hibernate.mapping.Property.isValid(Property.java:238)
    at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:468)
    at org.hibernate.mapping.RootClass.validate(RootClass.java:270)
    at org.hibernate.cfg.Configuration.validate(Configuration.java:1294)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1736)
    at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:94)
    at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:905)
    ... 56 more

Answer 1

问题在于，在您的IdEntity课程中，您注释了您的ID字段（而非getter），并且在子类User和Role中注释了您的getter，这是不一致的。您必须仅注释字段，或仅注释getter。有关类似问题，请参阅this问题。

或者，将@Access(AccessType.PROPERTY)添加到您的子类Role和User。

Answer 2

您的Set<Role> roles课程中没有名为User的属性。你怎么能编译这个？

当使用@MappedSuperclass，@ Entity，@ manytomany无法确定类型：java.util.Set

2 个答案: