具有两个参数的Hibernate CriteriaBuilder
问题描述:
我正在使用带有MySQL的Hibernate 5.2.1和JPA2的Java8。具有两个参数的Hibernate CriteriaBuilder
我有以下查询完美的作品:
final EntityManagerFactory entityManagerFactory = entityManager.getEntityManagerFactory();
final CriteriaBuilder criteriaBuilder = entityManagerFactory.getCriteriaBuilder();
CriteriaQuery<Rating> criteria = criteriaBuilder.createQuery(Rating.class);
Root<Rating> root = criteria.from(Rating.class);
ParameterExpression<Job> paramJob = criteriaBuilder.parameter(Job.class);
criteria.select(root).where(criteriaBuilder.equal(root.get("job"), paramJob));
正如你所看到的,查询有一个参数paramJob
。我想补充的第二个参数:
ParameterExpression<Person> paramPerson = criteriaBuilder.parameter(Person.class);
问题
如何修改以下行,以适应第二个参数?
criteria.select(root).where(criteriaBuilder.equal(root.get("job"), paramJob));
我可以只添加第二行:
criteria.select(root).where(criteriaBuilder.equal(root.get("person"), paramPerson));
感谢
答
试试这个:
criteria.select(root).where(
criteriaBuilder.equal(root.get("job"), paramJob),
criteriaBuilder.equal(root.get("person"), paramPerson)
);
答
更动态的方式在我的眼前。你将不得不调整一些东西,但这种方式,你也可以设置一个动态的where子句:
final EntityManagerFactory entityManagerFactory = entityManager.getEntityManagerFactory();
final CriteriaBuilder criteriaBuilder = entityManagerFactory.getCriteriaBuilder();
CriteriaQuery<Rating> criteria = criteriaBuilder.createQuery(Rating.class);
Root<Rating> root = criteria.from(Rating.class);
List<Predicate> predicates = new ArrayList<Predicate>();
predicates.add(criteriaBuilder.equal(root.get("job"), Job.class)); //might need to change ther Person.class to whatever matches the job
predicates.add(criteriaBuilder.equal(root.get("person"), paramPerson)); //same as above
criteria.select(root).where(predicates.toArray(new Predicate[]{}));
//execute query
谢谢你,工作。我会将此标记为正确答案。 – Richard