用JPA映射复合主键和外键

Question

我有两个表：A和B，都有一个复合主键。表B的PK也是表a主键的外键。

当我试图获取映射表B的类的实例时,我得到了以下异常：

org.hibernate.TypeMismatchException

@Entity @Table(name="usuarios")
public class UsuarioEntity implements Serializable {

    private static final long serialVersionUID = 1L;

    @EmbeddedId @AttributeOverrides( {
        @AttributeOverride(name="perTipoUsu", column=@Column(name="per_tipo_usu", nullable=false) ), 
        @AttributeOverride(name="perCodUsu", column=@Column(name="per_cod_usu", nullable=false) ) } )
    private UsuarioPKEntity pk = null;

   @OneToOne @PrimaryKeyJoinColumn
   private PersonaRelEnity personaRel = null;

   private String nombre;

   ....
}

@Entity @Table(name="persona_rel")
public class PersonaRelEnity implements Serializable {

    private static final long serialVersionUID = 1L;

    @EmbeddedId
    private PersonaRelPKEntity id;

    private String persona;

   ....
}

这两个类都位于package:com.cairone.ejemple01.entities

完整的日志输出为：

2016-09-21 12:28:24.505错误8568--[main]
O.S.Boot.SpringApplication：应用程序启动失败

java.lang.IllegalStateException: Failed to execute CommandLineRunner
  at     org.springframework.boot.SpringApplication.callRunner(SpringApplication.ja

2016-09-21 12:28:24.508信息8568--[main]utoConfigurationReportLoggingInitializer:

启动ApplicationContext时出错。要显示自动配置报告，请启用调试日志记录（从--debug开始）

2016-09-21 12:28:24.509  INFO 8568 --- [           main]     s.c.a.AnnotationConfigApplicationContext : Closing    

org.springframework.context.annotation.annotationconfigapplicationcontext@24b1d79b:启动日期[Wed Sep 21 12:28:21 ART 2016]；上下文层次结构的根2016-09-21 12:28:24.511 INFO 8568---[main]O.S.J.E.A.AnnotationMBeanExporter：关闭时注销JMX公开的bean 2016-09-21 12:28:24.513 INFO 8568---[main]J.LocalContainerEntityManagerFactoryBean：关闭持久性单元“default”的JPA
EntityManagerFactory

这是相关部分：

org.hibernate.TypeMismatchException：为类com.cairone.ejemploy01.entities.PersonareLenity提供了错误类型的id。应为：类com.cairone.ejcomple01.entities.personarelpkentity，已获得类com.cairone.ejcomple01.entities.usuariopkentity

Answer 1

这是一个“派生标识”，其中一个实体的主键是从另一个相关实体的主键派生的。

我没有遇到过和这种关系完全一样的事情，但试试这个：

@Entity
@Table(name="persona_rel")
public class PersonaRelEnity implements Serializable {

    @EmbeddedId
    private PersonaRelPKEntity pk;

    ...
}

@Embeddable
public class PersonaRelPKEntity implements Serializable {

    private static final long serialVersionUID = 1L;

    @Column(name="per_tipo")
    private Integer perTipo;

    @Column(name="per_cod")
    private Integer perCod;

    ...
}

@Entity
@Table(name="usuarios")
public class UsuarioEntity implements Serializable {

    @EmbeddedId
    private UsuarioEntityPK id;

    @OneToOne
    @MapsId("personaRelPKEntity")
    @JoinColumns({
        @JoinColumn(name="per_tipo_usu", referencedColumnName="per_tipo"),
        @JoinColumn(name="per_cod_usu", referencedColumnName="per_cod")
    })
    private PersonaRelEnity personaRelEntity = null;

    ...
}

@Embeddable
public class UsuarioEntityPK implements Serializable {

    // matches the PK type of PersonaRelEnity
    private PersonaRelPKEntity personaRelPKEntity;

    ...
}

派生标识在JPA2.1规范第2.4.1节中讨论。