在Service层中,我们将实现比较两个数的逻辑: importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.stereotype.Service;importjava.util.List;@ServicepublicclassUserService{@AutowiredprivateUserMapperuserMapper;publicvoidcompareAges(LonguserId1,LonguserId2){Useruser1=userMapper.sele...