java - JPA 标准生成仅包含一个问题点的查询

Question

在我们的数据库中，我们有缓存系统，什么对查询绑定(bind)参数敏感。

我创建了以下查询:

@Override
public Predicate toPredicate(Root<Position> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
    query.distinct(true);
    final Collection<Predicate> predicates = new ArrayList<>();

    Join<Position, ManagersPositions> managersPositionsJoin = root.join("managersPositions", JoinType.INNER);

    Predicate managerPredicate = criteriaBuilder.equal(managersPositionsJoin.get("managerId"), managerId);
    predicates.add(managerPredicate);

    if (onlyDirect) {
        Predicate equalsDirect = criteriaBuilder.equal(managersPositionsJoin.get("isDirect"), true);
        predicates.add(equalsDirect);
    }
    return criteriaBuilder.and(predicates.toArray(new Predicate[predicates.size()]));
}

它会产生以下查询:

select
   distinct position0_.id as id1_69_0_,
   ...
where managerspo1_.manager_id=22
and managerspo1_.is_direct=?

我必须发送带有 2 个绑定(bind)参数的请求，例如:

where managerspo1_.manager_id=?
and managerspo1_.is_direct=?

如何解决第一个“？”的问题？

Answer 1

使用 CriteriaBuilder.parameter() 添加多个参数:

    ParameterExpression<Integer> managerIdParam = 
        criteriaBuilder.parameter( Integer.class );
    ParameterExpression<Boolean> isDirectParam = 
        criteriaBuilder.parameter( Boolean.class );
    Predicate managerPredicate = 
        criteriaBuilder.equal(managersPositionsJoin.get("managerId"), 
        managerIdParam);
    Predicate equalsDirect = 
        criteriaBuilder.equal(managersPositionsJoin.get("isDirect"), isDirectParam);