Question

如何制作一个select语句或过滤一个嵌套在一个实体中的List？我有一个看起来像这样的对象......

@Entity
@Table(name = "employee")
public class Employee {

...

    @OneToMany(mappedBy = "_employee", fetch = FetchType.EAGER, cascade = CascadeType.REMOVE)
    @JsonManagedReference
    Set<Deal> _deals;

    @OneToMany(mappedBy = "_employee", fetch = FetchType.EAGER, cascade = CascadeType.REMOVE)
    @JsonManagedReference //This is simply to avoid a stackoverflow error according to this link http://stackoverflow.com/questions/3325387/infinite-recursion-with-jackson-json-and-hibernate-jpa-issue
    Set<Recommendation> _recommendations;


    @OneToMany(mappedBy = "_employee", fetch = FetchType.EAGER, cascade = CascadeType.REMOVE)
    @JsonManagedReference //This is simply to avoid a stackoverflow error according to this link http://stackoverflow.com/questions/3325387/infinite-recursion-with-jackson-json-and-hibernate-jpa-issue
    Set<Event> _events;

  public Employee() {
    }

//getters and setters

....

我让员工拥有一个由服务类访问的存储库。

存储库看起来像这样。

public interface EmployeeRepository extends CrudRepository<Employee, Long> {

    public Employee getEmployeeById(Long _id);

    public Employee getEmployeeBy_username(String username);

}

因此，当我通过其ID获得员工时，它会返回上面的列表。检索员工时，我需要以某种方式执行select语句或过滤_deals，_recommendations和_events。这样只有那些具有布尔属性_active = true的人才会返回。就像现在一样，所有交易建议和事件都会被返回，无论它们是否有效。如何过滤或从这些列表中仅选择活动对象？

Answer 1

您几乎总是为每个查询选择一个实体类型，最好是在数据库中进行过滤。如果您想要属于特定员工的交易，建议和事件，我通常会将这些方法放在属于实体类型I的存储库中，并尝试加载，它可能如下所示：

@Repository
public interface DealRepository extends JpaRepository<Deal, Long> {

    @Query("select d from Deal d where d.active= true and d.employee.id = :employeeId")
    List<Deal> findActiveDeals(@Param("employeeId") long employeeId);
}

如何在spring中包含在对象中的列表上创建select语句？

1 个答案: