hibernate uniqueResult方法

假设查询返回多个值用list()方法

1. public void testQuery(){
2. Configuration config = new Configuration().configure();
3. SessionFactory factory = config.buildSessionFactory(); //创建SessionFactory
4. Session session = factory.openSession();        //创建Session
5. session.beginTransaction();                     //開始事务
6. Query query = session.createQuery("from Student");
7. List list = query.list();  // 用list方法返回多个值
8. //List list = session.createQuery("from Student").list();
9. for(int i=0;i<list.size();i++){
10. Student student = (Student)list.get(i);
11. System.out.print(student.getId()+" ");
12. System.out.print(student.getName()+" ");
13. System.out.print(student.getSex()+" ");
14. System.out.print(student.getBirthday());
15. System.out.println();
16. }
17. session.getTransaction().commit();         //提交事务
18. session.close();                           //关闭Session
19. }

public void testQuery(){
		Configuration config = new Configuration().configure();
		SessionFactory factory = config.buildSessionFactory(); //创建SessionFactory
		Session session = factory.openSession();        //创建Session
		session.beginTransaction();                     //開始事务

		Query query = session.createQuery("from Student");
		List list = query.list();  // 用list方法返回多个值
		//List list = session.createQuery("from Student").list();
		for(int i=0;i<list.size();i++){
			Student student = (Student)list.get(i);
			System.out.print(student.getId()+" ");
			System.out.print(student.getName()+" ");
			System.out.print(student.getSex()+" ");
			System.out.print(student.getBirthday());
			System.out.println();
		}		

		session.getTransaction().commit();         //提交事务
		session.close();                           //关闭Session
	}

当确定返回的实例仅仅有一个或者null时 用uniqueResult()方法

1. public void testGet(){
2. Configuration config = new Configuration().configure();
3. SessionFactory factory = config.buildSessionFactory();
4. Session session = factory.openSession();
5. session.beginTransaction();
6. Query query = session.createQuery("from Student s where s.id=?");
7. query.setString(0, "2");
8. Student student = (Student)query.uniqueResult();  //当确定返回的实例仅仅有一个或者null时 用uniqueResult()方法
9. //Student student = (Student)session.createQuery("from Student s where s.id=?").setString(0,"5").uniqueResult();
10. System.out.println(student.getName());
11. System.out.println(student.getBirthday());
12. session.getTransaction().commit();
13. session.close();
14. }