MyBatis 注解查询一对一（@Results @One）

//在orderMapper里：
@Results({
    @Result(property = "id", column = "id"),
    @Result(property = "orderTime", column = "orderTime"),
    @Result(property = "total", column = "total"),
    @Result(property = "user", column = "uid", javaType = User.class,
        one = @One(select = "UserMapper.findUserById"))
})
@Select("select * from Order")
public List<Order> findOrderAndUser();

//在userMapper里：
@Select("select * from user where id = #{id}")
public User findUserById(Integer id);