Hibernate.cfg.xml

<!-- 设置默认事务隔离级别 
      读未提交      1
      读已提交      2
      可重复读      4
      串行化(不可并发)   8
    -->
    <property name="connection.isolation">2</property>


@Test
  public void test2() throws Exception {
    Session session = sessionFactory.openSession();// 打开Session
    Transaction tx = null;
    try {
      tx = session.beginTransaction();// 开始事务
      // ------------------------------------------------------------

      User user = (User) session.get(User.class, 2);// 持久化状态
      System.out.println(user.getName());

      session.refresh(user);// 刷新Session缓存中对象的状态,即重新select一下
      System.out.println(user.getName());

      // ------------------------------------------------------------
      tx.commit();// 提交事务
    } catch (Exception e) {
      tx.rollback();// 回滚事务
      throw e;
    } finally {
      session.close();// 释放资源
    }
  }