HIbernate 一对多关系只能保存一个

Question

org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [hibernate.student1#0]这是报错的信息这是测试类public class GSTest {private SessionFactory sessionFactory;   private Session session;   private Transaction transaction; @Before public void init(){ //创建配置对象 Configuration config=new Configuration().configure(); //config.addClass(Student.class); //创建服务注册对象 ServiceRegistry serviceRegistry =new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry(); //创建会话工厂对象 sessionFactory=config.buildSessionFactory(serviceRegistry); //会话对象 session=sessionFactory.openSession(); //开启事物 transaction=session.beginTransaction(); } @After public void destroy(){ transaction.commit();//提交事物 session.close();//关闭会话    sessionFactory.close();//关闭会话工厂 } @Test public void testSaveStudent(){  Grade g1=new Grade("java一班","java软件开发一班");     student1 stu1=new student1("王五","男");  student1 stu2=new student1("李四","男");  g1.getStudents().add(stu1);  g1.getStudents().add(stu2); session.save(g1);  session.save(stu1);  session.save(stu2); }}

Answer 1

报ID存入的ID有重复的，可以看看数据库里 SID是否设置了自动增加，相应的配置文件中 是否设置了自动增加