Hibernate: Criteria Query child objects (associations) by Entity (not Id)
I would like to query a Parent object by a list of child objects with Hibernate Criteria Query. I know how to do it with IDs of the childs but not using entities directly.
This works:
List<Long> listOfChildLongChildIds = new ArrayList<Long>();
listOfChildLongChildIds.add(new Long(1));
listOfChildLongChildIds.add(new Long(2));
Criteria criteria = getSession().createCriteria(Parent.class);
Criteria criteriaChilds = criteria.createCriteria("childs");
criteriaChilds.add(Restrictions.in("id", listOfChildLongChildIds));
But how to do this, when the list contains Child Objects/Entities like this:
List<Child> listOfChildEntities = new ArrayList<Child>();
listOfChildEntities.add(QueryChildFromDatabse);
listOfChildEntities.add(QueryChildFromDatabse);
(This means I do not use the ID of the child but only the Entitiy itself. The reason is otherwise I would have to iterate through my list of childs and extract all Ids and put them into a list what I think is most likely unnecessary. But I was not able to find any information how to query by entity lists itself):
Then the code above using
criteriaChilds.add(Restrictions.in("id",listOfChildEntities));
will throw an exception:
Child cannot be cast to java.lang.Long
我认为你应该能够做到这样的事情：
Criteria criteria = getSession().createCriteria(Parent.class);
criteria.createCriteria("childs","childs");
criteria.add(Restrictions.in("childs.id", listOfChildLongChildIds));
您应该能够将对象传递给Restrictions.in方法。
Restrictions.in("childs", <childObjectslist>)