AnnotationException：使用 @OneToMany 或 @ManyToMany 定位未映射的类

Question

我的用户超类：

@MappedSuperclass
public class User implements Serializable {

    @ManyToOne(targetEntity = Role.class, fetch = FetchType.EAGER)
    @JoinColumn(name = "roleId", referencedColumnName = "id")
    private Role role;

    other attributes ...

这是我的角色实体：

@Entity
public class Role implements GrantedAuthority {

    @JsonIgnore
    @OneToMany(mappedBy = "role", targetEntity = User.class, fetch = FetchType.LAZY)
    private Set<User> users = new HashSet<>();

    another attributes ...

我有这个用户类的子类：

@Entity
@Table
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
public class AUser extends User {
...
}

另一个子类：

@Entity
@Table
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
public class BUser extends User {
     ....
}

这是我的例外：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: com.x.y.model.Role.users[com.x.y.model.User]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1583) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1081) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:856) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) ~[spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) ~[spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
        at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:134) [spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
        at com.x.y.XApplication.main(XApplication.java:15) [classes/:na]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_60]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_60]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_60]
        at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_60]
        at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-1.4.2.RELEASE.jar:1.4.2.RELEASE]
Caused by: org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: com.x.y.model.Role.users[com.x.y.model.User]
        at org.hibernate.cfg.annotations.CollectionBinder.bindManyToManySecondPass(CollectionBinder.java:1191) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
        at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:794) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
        at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:719) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
        at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:54) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
        at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1655) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
        at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1623) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
        at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:278) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:847) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]
        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:874) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]
        at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) ~[spring-orm-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:353) ~[spring-orm-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:373) ~[spring-orm-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:362) ~[spring-orm-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1642) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1579) ~[spring-beans-4.3.4.RELEASE.jar:4.3.4.RELEASE]
        ... 20 common frames omitted

有人可以告诉我我的代码有什么问题吗？

Answer 1

您应该将 User 设为实体而不是 MappedSuperClass。如果您将 User 设为抽象类，则数据库中仍然不会有任何表。

但是，我想警告您在这种特殊情况下使用 TABLE_PER_CLASS 继承。table_per_class提供了更好的性能（选择特定使用已知类型时），但由于您只对每个会话进行身份验证用户，但性能无关紧要。

我正在研究具有 3 种类型的用户身份和 TABLE_PER_CLASS 继承的系统（回顾起来应该是 JOINED 继承）。问题是，如果 User 有一个 userName 属性并且您想要预先输入，则需要搜索 3 个表而不是一个（如果每个不同的 User 类型都引用了不同的实体，则情况可能会更糟）。最后，我们不得不向数据库添加一个视图，因为编写快速搜索 UI 所需的查询几乎是不可能的，因为我们使用了错误的继承策略。