为什么80%的码农都做不了架构师？>>> 
1、使用注解方式对mysql增删改查,它很方便，不像一些逆向工程工具一样生成的都是乱七八糟，虽然很全的方法，完全手写sql
基于上一篇博客，我们只需要新建一个目录dao层，然后创建UserDao.java 接口
public interface MybatisDao {@Insert({"insert into user(id,username,","password) values(#{id,jdbcType=VARCHAR},#{username,jdbcType=VARCHAR},","#{password,jdbcType=VARCHAR})"})int add(User user);@Delete({"delete from user where id =#{id,jdbcType=VARCHAR}"})int deleteUser(@Param("id")String id);@Update({"update user set username = #{username,jdbcType=VARCHAR}"})int updateUser(@Param("username")String username);@Select({"select id,username,password from user"})@Results({@Result(column = "id",property = "id",jdbcType = JdbcType.VARCHAR,id = true),@Result(column = "username",property = "username",jdbcType = JdbcType.VARCHAR),@Result(column = "password",property = "password",jdbcType = JdbcType.VARCHAR)})List<User> getUserList();@Select({"select id,username,password from user where id =#{id,jdbcType=VARCHAR}"})@Result(column = "password",property = "password",jdbcType = JdbcType.VARCHAR)User getOneUser(@Param("id")String id);}大概就这几个注解，@Insert、@Delete、@Update、@Select，分别对应增删该查，@Results @Result对应返回结果
