输入MapperScan注解后，再次运行出现了报错

问题描述：

输入MapperScan注解后，再次运行出现了报错

相关截图：

报错是这样的

Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userController': Unsatisfied dependency expressed through field 'userService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userServiceImpl': Unsatisfied dependency expressed through field 'userMapper'; nested exception is org.springframework.beans.factory.