使用 Criteria API 命令 BY

当我写一个 HQL 查询时

Query q = session.createQuery("SELECT cat from Cat as cat ORDER BY cat.mother.kind.value");
return q.list();

一切都很好。然而，当我写一个标准

Criteria c = session.createCriteria(Cat.class);
c.addOrder(Order.asc("mother.kind.value"));
return c.list();

我得到一个异常 org.hibernate.QueryException: could not resolve property: kind.value of: my.sample.data.entities.Cat

如果我想使用 Criteria 和 Order，我应该如何表达我的“ Order by”？

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小开

It's hard to know for sure without seeing the mappings (see @Juha's comment), but I think you want something like the following:

Criteria c = session.createCriteria(Cat.class);
Criteria c2 = c.createCriteria("mother");
Criteria c3 = c2.createCriteria("kind");
c3.addOrder(Order.asc("value"));
return c.list();
小开
最佳答案

You need to create an alias for the mother.kind. You do this like so.

Criteria c = session.createCriteria(Cat.class);
c.createAlias("mother.kind", "motherKind");
c.addOrder(Order.asc("motherKind.value"));
return c.list();
小开

You can add join type as well:

Criteria c2 = c.createCriteria("mother", "mother", CriteriaSpecification.LEFT_JOIN);
Criteria c3 = c2.createCriteria("kind", "kind", CriteriaSpecification.LEFT_JOIN);
小开

This is what you have to do since sess.createCriteria is deprecated:

CriteriaBuilder builder = getSession().getCriteriaBuilder();
CriteriaQuery<User> q = builder.createQuery(User.class);
Root<User> usr = q.from(User.class);
ParameterExpression<String> p = builder.parameter(String.class);
q.select(usr).where(builder.like(usr.get("name"),p))
.orderBy(builder.asc(usr.get("name")));
TypedQuery<User> query = getSession().createQuery(q);
query.setParameter(p, "%" + Main.filterName + "%");
List<User> list = query.getResultList();
小开

For Hibernate 5.2 and above, use CriteriaBuilder as follows

CriteriaBuilder builder = sessionFactory.getCriteriaBuilder();
CriteriaQuery<Cat> query = builder.createQuery(Cat.class);
Root<Cat> rootCat = query.from(Cat.class);
Join<Cat,Mother> joinMother = rootCat.join("mother");  // <-attribute name
Join<Mother,Kind> joinMotherKind = joinMother.join("kind");
query.select(rootCat).orderBy(builder.asc(joinMotherKind.get("value")));
Query<Cat> q = sessionFactory.getCurrentSession().createQuery(query);
List<Cat> cats = q.getResultList();

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