main2.start();
}
}
最后，执行测试主程序，在控制台中应该看到类似下面的输出：
Hibernate: select user0_.userId as userId0_0_, user0_.version as version0_0_, user0_.name as name0_0_, user0_.age as age0_0_ from USERINFO user0_ where user0_.userId=
Hibernate: select user0_.userId as userId0_0_, user0_.version as version0_0_, user0_.name as name0_0_, user0_.age as age0_0_ from USERINFO user0_ where user0_.userId=
Hibernate: update USERINFO set version= , name= , age= where userId= and version=
Hibernate: update USERINFO set version= , name= , age= where userId= and version=
2006-10-3 21:27:20 org.hibernate.event.def.AbstractFlushingEventListener performExecutions
严重: Could not synchronize database state with session
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [cn.hxex.hibernate.lock.User#1]
……
在Hibernate所执行的UPDATE语句中可以看到，version字段是作为更新的条件来执行的。对于第二个进程来说，由于数据库中的记录已经被第一个进程更新（更新的同时会导致version自动增加），就必然会导致第二个进程操作的失败。Hibernate正是利用这种机制来避免两次更新问题的出现。