1.代理开发模式

 UserMapper接口：

public interface UserMapper {public List<User> findAll() throws IOException;public User findById(int id) throws IOException;}

 UserMapper.XML：

<mapper namespace="com.example.dao.UserMapper"><!--查询操作--><select id="findAll" resultType="user">select * from user</select><!--根据id进行查询--><select id="findById" parameterType="int" resultType="user">select * from user where id = #{id}</select></mapper>

Test类：

public static void main(String[] args) throws IOException {InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);SqlSession sqlSession = sqlSessionFactory.openSession();UserMapper mapper = sqlSession.getMapper(UserMapper.class);List<User> all = mapper.findAll();System.out.println(all);User user = mapper.findById(1);System.out.println(user);}