Hibernate关联映射

 @Before
    public void myBefore(){
        cf = new Configuration().configure();
        // 2.创建SessionFactory
        SessionFactory sessionFactory = cf.buildSessionFactory();
        // 3. 打开session
        session = sessionFactory.getCurrentSession();
        // 4. 开始一个事务
        tx = session.beginTransaction();
    }
    @After
    public void myAfter() {
        tx.commit();
    }