mybatis使用注解开发

@Select    就是mapper里面的<select></select>

@Results    相当于<resultMap></resultMap>

@Result    相当于resultMap的字标签result   同时它的属性id是一个Boolean类型的值，如果为true，那么这个字段就是表的id，如果为false，那就是普通字段

@Select("select * from userinfo")
    @Results(id = "userMap",value = {
            @Result(id = true,property = "userId",column = "userId"),
            @Result(property = "username",column = "username"),
            @Result(property = "realName",column = "realName"),
            @Result(property = "sex",column = "sex"),
            @Result(property = "age",column = "age"),
            @Result(property = "accounts",column = "userId",many = @Many(
                    select = "com.zh.dao.AccountMapper.findAccountById",
                    fetchType = FetchType.LAZY
            ))
    })
    List<User> findAll();

    @Select("select * from userinfo where userId=#{userId}")
    User findById(Integer userId);