Spring boot JWT 토큰 생성

Jwt 인증 필터 

@Component
@RequiredArgsConstructor
public class JwtAuthenticationFilter extends OncePerRequestFilter {

    private final JwtService jwtService;
    private final MemberService memberService;

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        final String authHeader = request.getHeader("Authorization");
        final String jwt;
        final String username;
        if (authHeader == null || !authHeader.startsWith("Bearer ")) {
            filterChain.doFilter(request, response);
            return;
        }
        jwt = authHeader.substring(7);
        username = jwtService.extractUsername(jwt);
        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
            UserDetails userDetails = this.memberService.loadUserByUsername(username);
        }
    }
}

 

Jwt 서비스 코드 

Encryption Key Generator 에서 시크릿 키를 생성한다.

https://www.allkeysgenerator.com/Random/Security-Encryption-Key-Generator.aspx

Encryption Key Generator

@Service
public class JwtService {

    @Value("${secret_key}") // application.properties
    private static String SECRET_KEY;

    public String extractUsername(String token) {
        return extractClaim(token, Claims::getSubject);
    }

    public <T> T extractClaim(String token, Function<Claims, T> claimsResolver) {
        final Claims claims = extractAllClaims(token);
        return claimsResolver.apply(claims);
    }

    public String generateAccessToken(UserDetails userDetails) {
        return generateAccessToken(new HashMap<>(), userDetails);
    }

    public String generateAccessToken(
            Map<String, Object> extraClaims,
            UserDetails userDetails
    ){
        return Jwts
                .builder()
                .setClaims(extraClaims)
                .setSubject(userDetails.getUsername())
                .setIssuedAt(new Date(System.currentTimeMillis())) // 토큰 발행 시간
                .setExpiration(new Date(System.currentTimeMillis() + 1000 * 60 * 24)) // 토큰 만료 시간
                .signWith(getSignInKey(), SignatureAlgorithm.HS256) // 토큰 알고리즘
                .compact();
    }

    public boolean isTokenValid(String token, UserDetails userDetails) {
        final String username = extractUsername(token);
        return (username.equals(userDetails.getUsername())) && !isTokenExpired(token);
    }

    private boolean isTokenExpired(String token) {
        return extractExpiration(token).before(new Date());
    }

    private Date extractExpiration(String token) {
        return extractClaim(token, Claims::getExpiration);
    }

    private Claims extractAllClaims(String token) {
        return Jwts.parserBuilder()
                .setSigningKey(getSignInKey())
                .build()
                .parseClaimsJws(token)
                .getBody();
    }

    private Key getSignInKey() {
        byte[] keyBytes = Decoders.BASE64.decode(SECRET_KEY);
        return Keys.hmacShaKeyFor(keyBytes);
    }
}