JPA 映射 MAP<实体，可嵌入>

Question

我有两个类:

@Entity
@Table(name = "es_item")
public class Item {
    @Id
    @Column(name= "inventory_item_id")
    public int getInventoryItemID(){
        return inventoryItemID;
    }
    @ElementCollection(targetClass = ItemConversionAttributes.class, fetch = FetchType.LAZY)
    @MapKeyJoinColumn(name="component_item_id", referencedColumnName = "inventory_item_id")
    @CollectionTable(name="es_bom_levels", joinColumns = @JoinColumn(name = "inventory_item_id"))
    public Map<Item, ItemConversionAttributes> getConversionAttributes(){ return conversionAttributes; }
}
@Embeddable
public class ItemConversionAttributes {
    @ManyToOne(targetEntity=Item.class)
    @JoinColumn(name="component_item_id", insertable=false, updatable=false)
    @NotFound(action=NotFoundAction.IGNORE)
    public Item getComponentItem(){ return componentItem; }
}

db的结构是
es_item有列:inventory_item_id是key，一些其他的列
Es_bom_level包含:inventory_item_id, component_item_id。与component_item_id是fk到es_item。
我的映射不起作用。我看到错误
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: vmjboss7] Unable to build EntityManagerFactory at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:914) at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:889) at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:73) at org.jboss.as.jpa.service.PersistenceUnitServiceImpl.createContainerEntityManagerFactory(PersistenceUnitServiceImpl.java:162) at org.jboss.as.jpa.service.PersistenceUnitServiceImpl.start(PersistenceUnitServiceImpl.java:85) at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811) [jboss-msc-1.0.2.GA.jar:1.0.2.GA] at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746) [jboss-msc-1.0.2.GA.jar:1.0.2.GA] ... 3 more Caused by: org.hibernate.MappingException: Repeated column in mapping for collection: com.biz.model.Item.conversionAttributes column: component_item_id at org.hibernate.mapping.Collection.checkColumnDuplication(Collection.java:341) at org.hibernate.mapping.Collection.checkColumnDuplication(Collection.java:364) at org.hibernate.mapping.Collection.validate(Collection.java:321) at org.hibernate.mapping.IndexedCollection.validate(IndexedCollection.java:89) at org.hibernate.cfg.Configuration.validate(Configuration.java:1298) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1742) at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:84) at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:904)

Answer 1

很抱歉，因为我被其他问题困住了，所以延迟了回复:-

请尝试下面的代码:-

@Entity
@Table(name = "es_item")
public class Item {
    @Id
    @Column(name= "inventory_item_id")
    private int inventoryItemID;    
    @ElementCollection(fetch = FetchType.LAZY)   
    @CollectionTable(name="es_bom_levels", joinColumns = @JoinColumn(name = "component_item_id"))
    @MapKeyJoinColumn()
    public Map<Item, ItemConversionAttributes> conversionAttributes;
    ......
    // getters and setters
}
@Embeddable
class ItemConversionAttributes {
    @ManyToOne(targetEntity=Item.class)
    @JoinColumn(name="inventory_item_id", insertable=false, updatable=false)
    @NotFound(action=NotFoundAction.IGNORE)
    private Item componentItem;
    ..........
    // getters and setters
}

这里的一个问题是，这个设置在es_bom_levels表中创建了一个额外的列和约束，正如我在浏览了下面的博客

之后所期望的那样(我猜)。

mappingembeddable