传统开发方式
1.编写UserDao接口
public interface UserDao {
List<User> findAll() throws IOException;
}
2.编写UserDaoImpl实现
public class UserDaoImpl implements UserDao {
public List<User> findAll() throws IOException {
InputStream resourceAsStream =
Resources.getResourceAsStream("SqlMapConfig.xml");
SqlSessionFactory sqlSessionFactory = new
SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
List<User> userList = sqlSession.selectList("userMapper.findAll");
sqlSession.close();
return userList;
}
}
3.测试传统方式
@Test
public void testTraditionDao() throws IOException {
UserDao userDao = new UserDaoImpl();
List<User> all = userDao.findAll();
System.out.println(all);
}
代理开发方式
1.代理开发方式介绍
Mapper 接口开发方法只需要程序员编写Mapper 接口（相当于Dao 接口），由Mybatis 框架根据接口定义创建接口的动态代理对象，代理对象的方法体同上边Dao接口实现类方法
2.Mapper 接口开发需要遵循以下规范：
Mapper.xml文件中的namespace与mapper接口的全限定名相同Mapper接口方法名和Mapper.xml中定义的每个statement的id相同Mapper接口方法的输入参数类型和mapper.xml中定义的每个sql的parameterType的类型相同Mapper接口方法的输出参数类型和mapper.xml中定义的每个sql的resultType的类型相同 参考如图：
3.测试代理方式
@Test
public void testProxyDao() throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("SqlMapConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
//获得MyBatis框架生成的UserMapper接口的实现类
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User user = userMapper.findById(1);
System.out.println(user);
sqlSession.close();
}
