Hibernate 脏数据(session.isDirty())
持久对象总是与Session和Transaction相关联,在一个Session中,对持久对象的改变不会马上对数据库进行变更,而必须在Transaction终止,也就是执行commit()之后,才在数据库中真正运行SQL进行变更,持久对象的状态才会与数据库进行同步。在同步之前的持久对象称为脏(dirty)对象。
java代码片断如下:
public void sessionDirtyTest(){ User user=new User(); user.setUserid(new BigDecimal(1)); user.setLoginName("crabdave"); user.setUsername("David"); user.setPassword("David"); user.setSex("male"); user.setFixPhone("123456"); user.setMobilePhone("1234567890"); user.setDeleteFlag("1"); user.setStatus("1"); user.setAge("27"); user.setContract("1"); user.setDepartment("dept"); ApplicationContext ac = new FileSystemXmlApplicationContext("D:/PracticeWorkSpace/SSHPractice/src/main/resources/struts_1_spring.xml"); SessionFactory sessionFactory = ((HibernateTemplate)ac.getBean("hibernateTemplate")).getSessionFactory(); Session session=sessionFactory.openSession(); System.out.println("1.session.isDirty():"+session.isDirty()); Transaction tx=session.beginTransaction(); System.out.println("2.session.isDirty():"+session.isDirty()); tx.begin(); System.out.println("3.session.isDirty():"+session.isDirty()); session.update(user); System.out.println("4.session.isDirty():"+session.isDirty()); tx.commit(); System.out.println("5.session.isDirty():"+session.isDirty()); session.close(); System.out.println("6.session.isDirty():"+session.isDirty()); }
运行结果如下:
1.session.isDirty():false
2.session.isDirty():false
3.session.isDirty():false
4.session.isDirty():true
Hibernate: update user set loginName=?, username=?, password=?, sex=?, fixPhone=?, mobilePhone=?, deleteFlag=?, status=?, age=?, contract=?, department=? where userid=?
5.session.isDirty():false
Exception in thread "main" org.hibernate.SessionException: Session is closed!