java - EJB 3 预加载

Question

我使用 EJB 3。我有基类 A 和依赖类 B、C、D

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

    @OneToMany(cascade = CascadeType.ALL)
    private List<B> bs;

    @OneToMany(cascade = CascadeType.ALL)
    private List<C> cs;

    @OneToMany(cascade = CascadeType.ALL)
    private List<D> ds;

}

我有问题。我怎样才能急切地加载所有表格？我想使用 em.find(A.class, id);

Answer 1

您必须在 OneToMany 注释中使用 fetch 属性，以便:

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

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    private List<B> bs;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    private List<C> cs;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    private List<D> ds;

}