Spring Data JPA@Query具有规范

Question

select * from test.SCH_FORUM_THREAD t
where exists (select 'x' from test.FORUM_THREAD_ACCESS fta, school.SCH_GROUP_PERSON gp
                where gp.GROUP_ID = fta.GROUP_ID
                and t.THREAD_ID = fta.THREAD_ID
                and gp.PERSON_ID = :personId)
    or exists (select 'x' from test.FORUM_THREAD_ACCESS fta
                where fta.THREAD_ID = t.THREAD_ID
                and fta.PERSON_ID = :personId);

现在挣扎着与first存在，因为它已经加入了。有没有办法用规范来做到这一点。也因为有两个存在，这是否意味着我需要两个规范。我能在一个规范中实现它吗。

Answer 1

我能够通过创建一个复杂的规范代码来解决它。类似于

@Override
public Predicate toPredicate(Root<ForumThread> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
            Subquery<ForumThread> subQuery = query.subquery(ForumThread.class);
            Root<ForumThread> subRoot = subQuery.from(ForumThread.class);
            Join<ForumThreadAccess, GroupPerson> fragpjoin = subRoot.join("groupPersons");
            Predicate threadPredicate = builder.equal(root.get("threadId"), subRoot.get("threadId"));
            Predicate personPredicate = builder.equal(fragpjoin.get("personId"), personId); 
            subQuery.select(subRoot).where(threadPredicate, personPredicate);


            Predicate existsGroupPredicate = builder.exists(subQuery);


            Subquery<ForumThreadAccess> subQuery1 = query.subquery(ForumThreadAccess.class);
            Root<ForumThreadAccess> subRoot1 = subQuery1.from(ForumThreadAccess.class);
            Predicate threadPredicate1 = builder.equal(root.get("threadId"), subRoot1.get("threadId"));     
            Predicate personPredicate1 = builder.equal(subRoot1.get("personId"), personId); 
            subQuery1.select(subRoot1).where(threadPredicate1, personPredicate1);


            Predicate existsPersonPredicate = builder.exists(subQuery1);

            return builder.or(existsGroupPredicate,existsPersonPredicate);


        }

要使其正常工作，您的实体还应该有适当的@OneTomany和@ManyTomany。

谢谢