private static final Long ACCESS_TOKEN_EXPIRATION_TIME = 60 * 60 * 1000L;
  private static final Long REFRESH_TOKEN_EXPIRATION_TIME = 60 * 60 * 24 * 1000L * 14;

...
private final RedisTokenRepository redisTokenRepository;
....생략
  
  @Transactional
  public UserJoinResponse createMember(
      MemberCreateDto memberCreate
  ) {
    Member member = memberRepository.save(
        Member.create(memberCreate.name(), memberCreate.part(), memberCreate.age())
    );
    Long memberId = member.getId();
    String accessToken = jwtTokenProvider.issueAccessToken(
        UserAuthentication.createUserAuthentication(memberId)
    );
    String refreshToekn = jwtTokenProvider.issueRefreshToken(
        UserAuthentication.createUserAuthentication(memberId)
    );

    //리프레시 토큰 레디스에 저장(id는 memberId로..)
    redisTokenRepository.save(Token.of(memberId, refreshToekn));

    return UserJoinResponse.of(memberId.toString(), accessToken, refreshToekn);

  @PostMapping("/regenerate-token")
  public ResponseEntity<SuccessStatusResponse> regenerateToken(
      @RequestBody RegenerateAccessTokenRequestDto regenerateAccessTokenRequestDto
  ) {
    return ResponseEntity.ok()
        .body(SuccessStatusResponse.of(
            SuccessMessage.ACCESS_TOKEN_REGENERATE_SUCCESS,
            memberService.getNewAccessToken(regenerateAccessTokenRequestDto)));
  }

...
   private final RedisTokenRepository redisTokenRepository;
...생략
  
  @Transactional
  public RegenerateAccessTokenResponseDto getNewAccessToken(
      RegenerateAccessTokenRequestDto regenerateAccessTokenRequestDto) {

    String refreshToken = regenerateAccessTokenRequestDto.refreshToken();

    // 리프레시 토큰이 redis에 존재하는지 확인하기. 존재하면 만료되지 않은 것임.(일정 시간 후 사라지므로)
    // 없으면 다시 로그인하라는 에러메시지 보내기
    Token token = getRefreshToken(refreshToken);

    // 존재하는 토큰이 유효한 토큰인지(제대로 된 토큰인지) 다시 검증
    jwtTokenProvider.validateToken(token.getRefreshToken());

    // 유효하다면 액세스 토큰 재발급
    String accessToken = jwtTokenProvider.issueAccessToken(
        UserAuthentication.createUserAuthentication(token.getId())
    );

    return RegenerateAccessTokenResponseDto.of(accessToken);
  }
  
  ...생략
//redis에 refreshToken 존재하는지. 존재하면 리턴
   public Token getRefreshToken(String refreshToken) {
    return redisTokenRepository.findByRefreshToken(refreshToken).orElseThrow(
        () -> new UnauthorizedException(ErrorMessage.JWT_UNAUTHORIZED_REFRESH_EXPIRED_EXCEPTION));
  }