Mybatis编写dao的实现类

古城微笑少年丶 2023-02-20 07:51 14阅读 0赞

dao实现类impl

public class UserDaoImpl implements UserDao { 
    
        private SqlSessionFactory factory;
        public UserDaoImpl(SqlSessionFactory factory){ 
            this.factory = factory;
        }
    
        public List<User> findAll() { 
            //1.使用工厂创建session对象
            SqlSession session = factory.openSession();
            //2.使用session执行查询所有方法
            List<User> users = session.selectList("dao.UserDao.findAll");//namespace+id
            session.close();
            return users;
        }
    }

test

public class MybatisTest { 
        public static void main(String[] args)throws Exception { 
            //1.读取配置文件
            InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
            //2.创建SqlSessionFactory的构建者对象
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            //3.使用构建者创建工厂对象SqlSessionFactory
            SqlSessionFactory factory = builder.build(in);
    
            //4.使用SqlSessionFactory生产SqlSession对象
            //SqlSession session = factory.openSession();
            //5.使用SqlSession创建dao接口的代理对象
            //UserDao userDao = session.getMapper(UserDao.class);
    
    		//4.使用代理对象执行方法
    		UserDao userDao = new UserDaoImpl(factory);
    
    
            //5.使用代理对象执行查询所有方法
            List<User> users = userDao.findAll();
            for(User user : users)
            { 
                System.out.println(user);
            }
            //7.释放资源
            session.close();
            in.close();
        }
    }