[英]JPA Criteria select from another query
I am trying to select information from another query, like: 我正在尝试从另一个查询中选择信息,例如:
SELECT user.user_id, product.first_time
FROM USER AS user
INNER JOIN (SELECT min(product.first_time) as first_time,
product.user_id
FROM PRODUCT AS product
GROUP BY (product.user_id)
) product
ON user.user_id = product.user_id
but i don't know how to create a Criteria Query to execute it. 但我不知道如何创建条件查询来执行它。 Can I execute it with Criteria API? 我可以使用Criteria API执行它吗?
try using this: https://docs.jboss.org/hibernate/orm/4.3/topical/html/metamodelgen/MetamodelGenerator.html 尝试使用此: https : //docs.jboss.org/hibernate/orm/4.3/topical/html/metamodelgen/MetamodelGenerator.html
need to create metaclasses your's entities. 需要创建您的实体的元类。
example, your's service class: 例如,您的服务等级:
@Service("jpaCustomerService")
@Repository
@Transactional
public class CustomerServiceImpl implements CustomerService {
@PersistenceContext
private EntityManager em;
@Transactional(readOnly = true)
public List<CustomersEntity> findByCriteriaQuery(String name){
CriteriaBuilder cb = em.getCriteriaBuilder();
javax.persistence.criteria.CriteriaQuery<CustomersEntity> criteriaQuery = cb.createQuery(CustomersEntity.class);
Root<CustomersEntity> customersEntityRoot = criteriaQuery.from(CustomersEntity.class);
customersEntityRoot.fetch(CustomersEntity_.animal, JoinType.LEFT);
criteriaQuery.select(customersEntityRoot).distinct(true);
Predicate criteria = cb.conjunction();
if (!name.isEmpty()){
Predicate p = cb.equal(customersEntityRoot.get(CustomersEntity_.name), name);
criteria = cb.and(criteria, p);
}
criteriaQuery.where(criteria);
List<CustomersEntity> result = em.createQuery(criteriaQuery).getResultList();
return result;
}
}
and your's controller or your's main: 和您的控制者或您的主要人员:
public static void criteriaExample(GenericXmlApplicationContext ctx){
CustomerService service = ctx.getBean("jpaCustomerService", CustomerService.class);
List<CustomersEntity> creteriaResult = service.findByCriteriaQuery("NCI-3");
for (CustomersEntity customer : creteriaResult){
System.out.println(customer);
if (!customer.getAnimal().isEmpty())
for (AnimalsEntity animal : customer.getAnimal()){
System.out.println(animal);
}
}
}
CustomersEntity_ - metamodel class. CustomersEntity_-元模型类。 No needs SQL-query. 无需SQL查询。
and your's infs is: 而您的infs为:
public interface CustomerService {
List<CustomersEntity> findByCriteriaQuery(String name);}
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