java - 覆盖@CollectionTable

Question

我需要覆盖 JPA 中的集合表吗？也许有人有想法

 public class nationality{
       @Embedded
       @AttributeOverrides({
              @AttributeOverride(name="language.language", column = @Column(name="code_lang")) })
       private Language language;
    .....

语文课

@Embeddable
public class Language{
  @ElementCollection(fetch = FetchType.Eager)
  @CollectionTable(name="nat", joinColumns = @JoinColumn(name = "id"))
  private Collection<LanguageObj> language;
...
}

这是可行的，但@CollectionTable 链接必须出现在国籍类中。如何做到这一点？

Language 类必须被从不同表中获取数据的其他类重用。问题是表已经存在数据，所以无法编辑表比如从表country中获取数据的class country

public class country{
       @Embedded
       @AttributeOverrides({
              @AttributeOverride(name="language.language", column = @Column(name="code_country")) })
       private Language language;
    .....
}

Answer 1

解决办法
总体思路是:
1.在可嵌入对象中用@ElementCollection
注解集合字段 2. 在实体中使用@CollectionTable 注释collection getter。 getter 应该转发给 embeddable 的 getter。对于每个实体，您可以在 @CollectionTable 注释中指定单独的表名称

enum DayOfWeek {
    MONDAY,TUESDAY,...
}

@Embeddable
class ScheduleProperties {
    ...
    @ElementCollection
    private List<DayOfWeek> daysOfWeek;
    ...
    public List<DayOfWeek> getDaysOfWeek() {
        return daysOfWeek;
    }
}

@Entity
class SomeEntity {
    ...
    @Embedded
    private ScheduleProperties embd = new ScheduleProperties();
    ...
    @CollectionTable(name="some_entity_days_of_week")
    public List<DayOfWeek> getDaysOfWeek() {
        return embd.getDaysOfWeek();
    }
}

@Entity
class AnotherEntity {
    ...
    @Embedded
    private ScheduleProperties embd = new ScheduleProperties();
    ...
    @CollectionTable(name="another_entity_days_of_week")
    public List<DayOfWeek> getDaysOfWeek() {
        return embd.getDaysOfWeek();
    }
}