CriteriaBuilder.and & CriteriaBuilder.or, how-to?

问题

I'm trying to change the following HQL to use JPA Criteria:

select distinct d from Department d 
left join fetch d.children c 
where d.parent is null 
and (
    d.name like :term 
    or c.name like :term
    ) 
order by d.name

Department has a Set<Department> of children.

Criteria:

CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
CriteriaQuery<Department> c = cb.createQuery(Department.class);
Root<Department> root = c.from(Department.class);
root.fetch("children", JoinType.LEFT);
Path<Department> children = root.join("children", JoinType.LEFT);
c.orderBy(cb.asc(root.get("name")));
c.distinct(true);
c.where(cb.isNull(root.get("parent")));
String param = "%" + "term" + "%";
cb.and(cb.like(root.<String> get("name"), param));
cb.or(cb.like(children.<String> get("name"), param));

TypedQuery<Department> tq = getEntityManager().createQuery(c);
departments = tq.getResultList();

I know it can be a bit terse, however, the HQL returns 24 and Criteria version 28. I think I'm not handling:

and (x = y OR z = y)

correctly. Any pointers will be greatly appreciated. Thanks.

回答1:

Here's the where clause of your JPQL query:

where d.parent is null 
and (
    d.name like :term 
    or c.name like :term
    )

The where clause contains two predicates:

d.parent is null

and

(d.name like :term 
 or c.name like :term)

The second predicate is an or containing two predicates:

d.name like :term

and

c.name like :term

So you need the same structure in your criteria query:

Predicate orClause = 
    cb.or(cb.like(root.<String>get("name"), param),
          cb.like(children.<String>get("name"), param));

c.where(cb.isNull(root.get("parent")),
        orClause);

来源：https://stackoverflow.com/questions/18069449/criteriabuilder-and-criteriabuilder-or-how-to

标签

jpa-2.0

criteria-api