不能识别dao

请问有遇到这个问题的么：org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [spring/spring-dao.xml]: Invocation of init method failed; nested exception is java.lang.NoClassDefFoundError: org/seckill/dao/seckillDao (wrong name: org/seckill/dao/SeckillDao)

我是新手，所以是跟着老师来的