在JPA中保留地图

Question

I have the following classes

class Category {
    Long id;
}
class Question  {
    Long id;

    @OneToOne (cascade=CascadeType.ALL)
    Category category;
}
class Test   {
    Long id;    
    Map<Category, Long> splitUp;
}

These are partial versions of the my classes, I have annotated the category and Quesiton classes but having trouble annotating the map "splitUp" in the Test Class. I would like some help in that.

Answer 1

class Test   {
    Long id;    

    @ElementCollection
    @JoinTable(name = "CATEGORY_JOIN_TABLE", joinColumns = @JoinColumn(name = "category_join_table_id_column"))
    @MapKeyJoinColumn (name = "category_id")
    @Column(name = "id")
    Map<Category, Long> splitUp;
}

This should work.