排序查询

 /**
     * 排序查询：倒叙查询所有客户（根据 id倒序）
     *      sql:   SELECT * FROM cst_customer ORDER BY cust_id DESC
     *      jqpl:  from Customer order by custId desc
     *
     * 进行jpql查询
     *      1.创建query对象
     *      2.对参数进行赋值
     *      3.查询并得到返回结果
     */
    @Test
    public void testOrders(){
        //1.获取entityManager对象
        EntityManager entityManager = JpaUtils.getEntityManager();
        //2.开启事务
        EntityTransaction transaction = entityManager.getTransaction();
        transaction.begin();
        //3.查询全部
        String jpql = "from Customer order by custId desc";
        Query query = entityManager.createQuery(jpql);
        // 发送查询，封装结果集
        List list = query.getResultList();
        for(Object obj : list){
            System.out.println(obj);
        }
        //4.提交事务
        transaction.commit();
        //5.释放资源
        entityManager.close();
    }