spring data jpa 查询时的统计

public List<SimpleCity> listByProvinceId(int provinceId) {
        EntityManager em = entityManagerFactory.createEntityManager();
        Query query = em.createQuery("select new com.jiapeng.xfw.server.normalClass.SimpleCity(c.province.id,c.province.name,c.id,c.name,c.distList.size) " +
                "from City c where c.province.id =?  order by c.id");
        query.setParameter(1,provinceId);
        List<SimpleCity> list = query.getResultList();
        em.close();
        return list;
    }

c.distList.size就是统计的，在City类中定义的属性是这样的

@OneToMany(mappedBy = "city")
    private