public void regist(RegisterRequest req) {
   // 동일한 이메일을 갖는 회원 데이터가 존재하는지 확인
   Member member = memberDao.selectByEmail(req.getEmail());
   if (member != null) {
     throw new AlreadyExistingMemberException("dup email " + req.getEmail());
   }
   Member newMember = new Member(req.getEmail(), req.getPassword(), req.getName(), new Date());
   memberDao.insert(newMember);
 }