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  • Hibernate之Query接口的uniqueResult()方法

    如果查询返回多个值用list()方法

    public void testQuery(){
    		Configuration config = new Configuration().configure();
    		SessionFactory factory = config.buildSessionFactory(); //创建SessionFactory
    		Session session = factory.openSession();        //创建Session
    		session.beginTransaction();                     //开始事务
    		
    		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
    	}
    
    
    当确定返回的实例只有一个或者null时 用uniqueResult()方法

    public void testGet(){
    		Configuration config = new Configuration().configure();
    		SessionFactory factory = config.buildSessionFactory();
    		Session session = factory.openSession();
    		session.beginTransaction();
    		
    		Query query = session.createQuery("from Student s where s.id=?");
    		query.setString(0, "2");
    		Student student = (Student)query.uniqueResult();  //当确定返回的实例只有一个或者null时 用uniqueResult()方法
    		//Student student = (Student)session.createQuery("from Student s where s.id=?").setString(0,"5").uniqueResult();
    		
    		System.out.println(student.getName());
    		System.out.println(student.getBirthday());
    		
    	
    		session.getTransaction().commit();
    		session.close();
    	}


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  • 原文地址:https://www.cnblogs.com/itmyhome/p/4131569.html
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