我正在使用Spring MVC和Hibernate开发一个Web应用程序。问题是,我需要向我的所有客户展示,每个客户都有另一个相关的实体("Cobrador",对不起,我不知道这里的英文翻译),我使用JQgrid来实现这个目标。当我执行网格时,我在日志中看到:
Hibernate: select cliente0_.id as id1_0_, cliente0_.activo as activo2_0_, cliente0_.apellido as apellido3_0_, cliente0_.cobrador as cobrador8_0_, cliente0_.dni as dni4_0_, cliente0_.email as email5_0_, cliente0_.nombre as nombre6_0_, cliente0_.telefono as telefono7_0_ from clientes cliente0_ where cliente0_.activo=1
Hibernate: select cobrador0_.id as id1_1_0_, cobrador0_.activo as activo2_1_0_, cobrador0_.apellido as apellido3_1_0_, cobrador0_.dni as dni4_1_0_, cobrador0_.email as email5_1_0_, cobrador0_.nombre as nombre6_1_0_, cobrador0_.telefono as telefono7_1_0_ from cobradores cobrador0_ where cobrador0_.id=?
Hibernate: select cobrador0_.id as id1_1_0_, cobrador0_.activo as activo2_1_0_, cobrador0_.apellido as apellido3_1_0_, cobrador0_.dni as dni4_1_0_, cobrador0_.email as email5_1_0_, cobrador0_.nombre as nombre6_1_0_, cobrador0_.telefono as telefono7_1_0_ from cobradores cobrador0_ where cobrador0_.id=?
Hibernate: select cobrador0_.id as id1_1_0_, cobrador0_.activo as activo2_1_0_, cobrador0_.apellido as apellido3_1_0_, cobrador0_.dni as dni4_1_0_, cobrador0_.email as email5_1_0_, cobrador0_.nombre as nombre6_1_0_, cobrador0_.telefono as telefono7_1_0_ from cobradores cobrador0_ where cobrador0_.id=?
基本上是获取客户端,然后,为每个客户端go获取相关的"cobrador"。我的客户端实体配置如下:
@Entity
@Table(name="clientes")
public class Cliente {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String apellido;
private String nombre;
private int dni;
private String telefono;
private String email;
private boolean activo;
@ManyToOne
@JoinColumn(name="cobrador")
@Fetch(FetchMode.JOIN)
private Cobrador cobrador;
//Contructors, getters and setters
}
BTW:最后的休眠执行是:
@Override
@Transactional
public List<T> getAllFiltering(String filter) {
Query q = sessionFactory.getCurrentSession().createQuery("from " + type.getSimpleName() + " " + filter);
return q.list();
}
Where为,filter为"Where activo=true"。
是否有配置此关系以便在加载网格时只执行一个查询?
提前感谢!
我知道这不是很方便,但如果您使用HQL
查询(即使用createQuery方法),Hibernate
将不会使用提取策略。如果要使其工作,则必须使用Criteria
API或在HQL查询中指定联接。
在您的情况下,查询可能是这样的:
from Cliente c left join fetch c.cobrador
来自Hibernate文档:
映射文档中定义的提取策略影响:
- 通过get()或load()检索
- 导航关联时隐式发生的检索
- 条件查询
- HQL查询是否使用了子选择提取
正如您所看到的,定义的获取策略不会影响HQL查询如果JOIN是fetchMode。