在hibernate使用CriteriaBuilder时，如何立即向左添加条件，而不是作为where条件的一部分？

Question

我希望criteriabuilder立即用join（查询下面左1个join）进行置入和条件。但是当我把condition放在谓词中时，它会把if添加到final where子句

我想要这样的输出：

    select
            *
        from
            milestone milestone0_ 
        left outer join
            disc_user_milestone_watch userswatch1_ 
                on milestone0_.id=userswatch1_.milestone_id AND userswatch1_.disc_user_id=2  
        left outer join
            disc_user discuser2_ 
                on userswatch1_.disc_user_id=discuser2_.id cross 
        join
            campaign campaign3_ cross 
        join
            department department4_ 
        where
            milestone0_.campaign=campaign3_.id 
            and milestone0_.department=department4_.id;

    select
            *
        from
            milestone milestone0_ 
        left outer join
            disc_user_milestone_watch userswatch1_ 
                on milestone0_.id=userswatch1_.milestone_id   
        left outer join
            disc_user discuser2_ 
                on userswatch1_.disc_user_id=discuser2_.id cross 
        join
            campaign campaign3_ cross 
        join
            department department4_ 
        where
            milestone0_.campaign=campaign3_.id 
            and milestone0_.department=department4_.id 
            AND userswatch1_.disc_user_id=2;

    EntityManager em = Milestone.entityManager();
    CriteriaBuilder criteriaBuilder = em.getCriteriaBuilder();
    CriteriaQuery criteriaQuery = criteriaBuilder.createQuery(UserMilestoneWatchStatus.class);

    Root milestoneRoot = criteriaQuery.from(Milestone.class);
    Join milestonediscUserJoin = milestoneRoot.join("usersWatching", JoinType.LEFT);

    // this is used for extending the milestone table to the user table
    Expression userId = milestonediscUserJoin.get("id"); // id
    int currUserId = Integer.parseInt(params.get("currUserId").toString());

    milestoneRoot.alias("x");
    criteriaQuery.select(criteriaBuilder.construct(UserMilestoneWatchStatus.class, milestoneRoot, userId));
    criteriaQuery.distinct(true);

    List predicatesList = new ArrayList();
    predicatesList.add(criteriaBuilder.or(criteriaBuilder.equal(userId, currUserId), criteriaBuilder.isNull(userId)));

    criteriaQuery.where(criteriaBuilder.and(predicatesList.toArray(new Predicate[predicatesList.size()]))).orderBy(sort);

Answer 1

不，没办法那样做。JPA2.0不支持with ON子句join。它可能会成为JPA2.1的一部分。