Question

我如何仅获得来自给定用户的实体

public List<T> findRangeByUser(int[] range, User user) {
    javax.persistence.criteria.CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
    javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
    Predicate condition = cb.equal(cq.from(User.class), user);
    cq.select(cq.from(entityClass));
    cq.where(condition);
    javax.persistence.Query q = getEntityManager().createQuery(cq);
    q.setMaxResults(range[1] - range[0]);
    q.setFirstResult(range[0]);
    return q.getResultList();
}

我应该怎样解决这个问题？另请注意，用户是引用User表中userId的外键目前正在归还所有物品非常感谢你

Answer 1

条件构建器需要一个条件来评估返回结果的用户ID。像这样：

Predicate condition = qb.equal(root.get(field), usuerController.getUserSession().getUser().getIdUser());
critera.where(condition);

将“field”替换为引用用户ID的SingularAttribute。

Answer 2

public List<T> findRangeByUser(int[] range, User user) {
    javax.persistence.criteria.CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
    javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
    javax.persistence.criteria.Root<T> rt = cq.from(entityClass);     
    cq.where(cb.equal(rt.get("useridUser"), user));
    javax.persistence.Query q = getEntityManager().createQuery(cq);
    q.setMaxResults(range[1] - range[0]);
    q.setFirstResult(range[0]);
    return q.getResultList();
}

JPA如何将过滤器应用于EJB criteriaquery

2 个答案: