org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.executor.ExecutorException:
A query was run and no Result Maps were found for the Mapped Statement 'com.demo.dao.UserDao.check'. It's likely that neither a Result Type nor a Result Map was specified.
改为，这是因为没有写返回类型出错
修改后clean Tomcat；
修改完成后，项目还不能执行，可能是Tomcat，不刷新，
修改如图配置，修改成功再次执行即可解决。