Hibernate @Embeddable类扩展了另一个@Embeddable类,找不到@OneToMany映射的属性

Question

我们正在将旧的基于xml的配置转换为基于注释的配置

情况

有一个类被注释为@Embeddable(ParentPk.java),另一个类扩展了这个类 @Embeddable(ChildPk.java),这个ChildPk.java被用作复合主键SomeOwnerClass.java,它与另一个类有外来关系,SomeChildTable.java并倾向于使用父类中可用的属性col1和col2的 ChildPk.java,但在执行查询Hibernate没有发现COL1和COL2,而如果我复制COL1和COL2在ChildPk.java从父类中的每一件事工作正常.

下面是代码片段,SomeOwnerClass.java它引用了col1和col2

>  @OneToMany(orphanRemoval = true, fetch=FetchType.EAGER)
>        @Cascade(value = {CascadeType.ALL,CascadeType.SAVE_UPDATE})
>        @Fetch(FetchMode.JOIN)
>        @JoinColumns({
>        @JoinColumn(name="COL_1",insertable=false,updatable=false,referencedColumnName="COL_1"),
>        @JoinColumn(name="COL_2",insertable=false,updatable=false,referencedColumnName="COL_2"),
>        @JoinColumn(name="COL_3",insertable=false,updatable=false,referencedColumnName="COL_3"),
>     })    private Set<SomeChildTable> collection = new
> HashSet<SomeChildTable>();

针对这种情况的解决方案？

ParentPk.java

 @Embeddable
    public class ParentPk implements Serializable  {

        @Column(name="COL_1")
        private String col1;

        @Column(ame="COL_2")
        private String col2;

    }

ChildPk.java

@Embeddable
public class ChildPk extends ParentPk implements Serializable  {

    @Column(name="COL_3")
    private String col3;
}

SomeOwnerClass.java

@Entity
@Table(name="FOO")
public class SomeOwnerClass implements Serializable  {

    @EmbeddedId
       @AttributeOverrides({@AttributeOverride(name="col1", column=@Column(name="COL_1",length=38))})
        private ChildPk childPk = new ChildPk();

         @OneToMany(orphanRemoval = true, fetch=FetchType.EAGER)
         @Cascade(value = {CascadeType.ALL,CascadeType.SAVE_UPDATE})
         @Fetch(FetchMode.JOIN)
         @JoinColumns({
         @JoinColumn(name="COL_1",insertable=false,updatable=false,referencedColumnName="COL_1"),
         @JoinColumn(name="COL_2",insertable=false,updatable=false,referencedColumnName="COL_2"),
         @JoinColumn(name="COL_3",insertable=false,updatable=false,referencedColumnName="COL_3"),
      })
    private Set<SomeChildTable> collection = new HashSet<SomeChildTable>();
}

例外

org.hibernate.MappingException: Unable to find column with logical name: COL_1 in SomeOwnerClass
    at org.hibernate.cfg.Ejb3JoinColumn.checkReferencedColumnsType(Ejb3JoinColumn.java:587)
    at org.hibernate.cfg.BinderHelper.createSyntheticPropertyReference(BinderHelper.java:258)
    at org.hibernate.cfg.annotations.CollectionBinder.bindCollectionSecondPass(CollectionBinder.java:1451)
    at org.hibernate.cfg.annotations.CollectionBinder.bindOneToManySecondPass(CollectionBinder.java:864)
    at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:779)
    at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:728)
    at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:70)
    at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1695)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1424)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1844)
    at com.foo.mypackage.ParentHibernateUtil.initiateSessionFactory(ParentHibernateUtil.java:112)
    at com.foo.mypackage.ParentHibernateUtil.getSessionFactory(ParentHibernateUtil.java:131)
    at com.foo.mypackage.GenericHibernateDAO.getSession(GenericHibernateDAO.java:36)
    at com.foo.mypackage.GenericHibernateDAO.beginTransaction(GenericHibernateDAO.java:63)
    at com.foo.mypackage.MarsTest.main(MyTest.java:22)

其他细节 我试图将基于xml的配置映射到基于注释的配置,这是基于旧的基于xml的配置,在继承方面工作正常.

ChildPk.java转换为扩展ParentPk.java的@Embedable

<class name="SomeOwnerClassDetail" table="FOO_DETAIL">

        <composite-id class="ChildPk"
            name="childPk">
            <key-property name="col1" column="COL_1"  type="java.lang.Long"/>
            <key-property name="col2" column="COL_2" length="32"/>
            <key-property name="col3" column="COL_3" length="3"/>
        </composite-id>
    </class>

在上面的映射中,col1和col2是从ParentPk.java继承的,如果ChildPk在xml映射中的SomeOwnerClass.java中用作外键但在带注释的映射中不能使用.

我不能改变我的类的结构,因为它是遗留应用程序.

SomeOwnerClass.java

<set name="someDetailKey" cascade="all,delete-orphan,save-update" lazy="false" fetch="join"  > 
        <key foreign-key="FOO_Foreign_Key" >
            <column name="COL_1"/>
            <column name="COL_2"/>
            <column name="COL_3"/>
        </key>
        <one-to-many class="ChildPk" />
    </set>

Answer 1

您可以在@Embeddable类之间实现继承.您只需要注释父类@MappedSuperclass.

所以,例如:

@Embeddable
@MappedSuperclass
public class Parent {
    @Basic
    private String parentProperty;

    // ... getters/setters
}

@Embeddable
public class Child extends Parent {
    @Basic
    private String childProperty;

    // ... getters/setters
}

这样的Hibernate(与5.x的测试)将映射都parentProperty和childProperty在正确Child类.

Answer 2

Hibernate不支持@Embeddable组件的继承:

无法直接保持或查询可嵌入对象,只能在其父对象的上下文中对其进行持久化或查询.可嵌入对象没有id或table.JPA规范不支持具有继承的可嵌入对象,尽管一些JPA提供程序可能允许这样做.

- Java_Persistence/Embeddables.

JPA规范不支持具有继承的可嵌入对象
因此您无法使用继承@Embeddable.

您可以尝试通过将父ID作为子ID的属性来完成它.