JPA Embeddable class 可以包含 object 參考嗎？

Question

我正在嘗試將 class 嵌入到另一個包含 object 引用的對象中。 我總是得到

org.hibernate.MappingException: Could not determine type for: ...

例外。 我的問題是有什么方法可以嵌入包含 object 引用的 class，或者可嵌入類僅存儲原語。

我已經嘗試過 @Target() 注釋但沒有幫助。

Answer 1

是的，這是可能的。 查看文檔。

@Embeddable
public static class Publisher {

    private String name;

    @ManyToOne(fetch = FetchType.LAZY)
    private Country country;

    //Getters and setters, equals and hashCode methods omitted for brevity
}


@Entity(name = "Book")
@AttributeOverrides({
    @AttributeOverride(
        name = "ebookPublisher.name",
        column = @Column(name = "ebook_publisher_name")
    ),
    @AttributeOverride(
        name = "paperBackPublisher.name",
        column = @Column(name = "paper_back_publisher_name")
    )
})
@AssociationOverrides({
    @AssociationOverride(
        name = "ebookPublisher.country",
        joinColumns = @JoinColumn(name = "ebook_publisher_country_id")
    ),
    @AssociationOverride(
        name = "paperBackPublisher.country",
        joinColumns = @JoinColumn(name = "paper_back_publisher_country_id")
    )
})
public static class Book {

    @Id
    @GeneratedValue
    private Long id;

    private Publisher ebookPublisher;

    private Publisher paperBackPublisher;

    //Getters and setters are omitted for brevity
}