@SuppressWarnings("unused")

    @Test

    // 配置二级缓存的情况

    public void demo2(){

        Session session = HibernateUtils.getCurrentSession();

        Transaction tx = session.beginTransaction();

        Customer customer1 = (Customer) session.get(Customer.class, 1);// 发送SQL.

        Customer customer2 = (Customer) session.get(Customer.class, 1);// 不发送SQL.

        System.out.println(customer1 == customer2);

        tx.commit();//

        session = HibernateUtils.getCurrentSession();

        tx = session.beginTransaction();

        Customer customer3 = (Customer) session.get(Customer.class, 1);// 不发送SQL. 虽然是从二级缓存里获取的一个数据同时它也会往一级缓存里面放

        //因为上一个一级缓存已经结束了,这是另一个session的一级缓存了。所以customer4肯定是从一级缓存获取的

        Customer customer4 = (Customer) session.get(Customer.class, 1);// 不发送SQL.

        System.out.println(customer3 == customer4);//customer3和customer4肯定也是一样的

        System.out.println(customer1 == customer3);//Customer对象肯定是在二级缓存的类缓冲区里面的 那么二级缓存的类缓冲区是一个什么特点呢？二级缓存的类缓冲区卡里面存储的数据是

        //对象的散装数据  

        tx.commit();

    }

    @SuppressWarnings("unused")

    @Test

    // 没有配置二级缓存的情况

    public void demo1(){

        Session session = HibernateUtils.getCurrentSession();

        Transaction tx = session.beginTransaction();

        Customer customer1 = (Customer) session.get(Customer.class, 1);// 发送SQL.

        Customer customer2 = (Customer) session.get(Customer.class, 1);// 不发送SQL.

        //一级缓存缓存的是对象的地址,cutoemr1和customer2指向的都是同一个地址

        System.out.println(customer1==customer2);

        tx.commit();

        session = HibernateUtils.getCurrentSession();

        tx = session.beginTransaction();

        Customer customer3 = (Customer) session.get(Customer.class, 1);// 发送SQL.

        tx.commit();

    }

}