feat: JwtUtil 구현

- 토큰 생성, 저장, Claims 추출, 만료 등의 작업 수행

Author: ysw789

src/main/java/dmu/dasom/api/global/auth/jwt/JwtUtil.java

@@ -0,0 +1,133 @@
+package dmu.dasom.api.global.auth.jwt;
+
+import dmu.dasom.api.domain.common.exception.CustomException;
+import dmu.dasom.api.domain.common.exception.ErrorCode;
+import dmu.dasom.api.global.auth.dto.TokenBox;
+import io.jsonwebtoken.*;
+import io.jsonwebtoken.security.SignatureException;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.stereotype.Component;
+
+import javax.crypto.SecretKey;
+import javax.crypto.spec.SecretKeySpec;
+import java.nio.charset.StandardCharsets;
+import java.util.Date;
+import java.util.concurrent.TimeUnit;
+
+@Component
+public class JwtUtil {
+
+    @Value("${jwt.access-token-expiration}")
+    private long accessTokenExpiration;
+
+    @Value("${jwt.refresh-token-expiration}")
+    private long refreshTokenExpiration;
+
+    private static final String ACCESS_TOKEN_PREFIX = "ACCESS_";
+    private static final String REFRESH_TOKEN_PREFIX = "REFRESH_";
+    private static final String BLACKLIST_PREFIX = "BLACKLIST_";
+
+    private final SecretKey secretKey;
+    private final StringRedisTemplate redisTemplate;
+
+    public JwtUtil(@Value("${jwt.secret}") final String secretKey, final StringRedisTemplate redisTemplate) {
+        this.secretKey = new SecretKeySpec(secretKey.getBytes(StandardCharsets.UTF_8), Jwts.SIG.HS256.key().build().getAlgorithm());
+        this.redisTemplate = redisTemplate;
+    }
+
+    // Access, Refresh 토큰 생성
+    public TokenBox generateTokenBox(final String email) {
+        final TokenBox tokenBox = TokenBox.builder()
+                .accessToken(generateToken(email, accessTokenExpiration))
+                .refreshToken(generateToken(email, refreshTokenExpiration))
+                .build();
+
+        saveTokens(tokenBox, email);
+
+        return tokenBox;
+    }
+
+    // 토큰 생성
+    public String generateToken(final String email, final long expirationMs) {
+        return Jwts.builder()
+                .issuer("dmu-dasom.or.kr")
+                .subject(email)
+                .issuedAt(new Date(System.currentTimeMillis()))
+                .expiration(new Date(System.currentTimeMillis() + expirationMs))
+                .signWith(this.secretKey)
+                .compact();
+    }
+
+    // 토큰 저장
+    public void saveTokens(final TokenBox tokenBox, final String email) {
+        redisTemplate.opsForValue().set(ACCESS_TOKEN_PREFIX.concat(email), tokenBox.getAccessToken(), accessTokenExpiration, TimeUnit.MILLISECONDS);
+        redisTemplate.opsForValue().set(REFRESH_TOKEN_PREFIX.concat(email), tokenBox.getRefreshToken(), refreshTokenExpiration, TimeUnit.MILLISECONDS);
+    }
+
+    // Request 헤더에서 토큰 추출
+    public String parseToken(final String authHeaderValue) {
+        return authHeaderValue.split(" ")[1];
+    }
+
+    // 토큰으로부터 Claims 추출
+    public Claims parseClaims(final String token) {
+        try {
+            return Jwts.parser()
+                    .verifyWith(this.secretKey)
+                    .build()
+                    .parseSignedClaims(token)
+                    .getPayload();
+        } catch (SecurityException | MalformedJwtException | SignatureException |
+                 UnsupportedJwtException | IllegalArgumentException | ClaimJwtException e) {
+            throw new CustomException(ErrorCode.TOKEN_NOT_VALID);
+        }
+    }
+
+    // 토큰의 남은 수명 반환
+    public long getRemainingTokenExpiration(final String token) {
+        return parseClaims(token).getExpiration().getTime() - System.currentTimeMillis();
+    }
+
+    // Access, Refresh 토큰 블랙리스트 추가
+    public void blacklistTokens(final String email) {
+        final String accessTokenKey = ACCESS_TOKEN_PREFIX.concat(email);
+        final String refreshTokenKey = REFRESH_TOKEN_PREFIX.concat(email);
+
+        if (redisTemplate.hasKey(accessTokenKey)) {
+            blacklistToken(redisTemplate.opsForValue().get(accessTokenKey));
+            redisTemplate.delete(accessTokenKey);
+        }
+
+        if (redisTemplate.hasKey(refreshTokenKey)) {
+            blacklistToken(redisTemplate.opsForValue().get(refreshTokenKey));
+            redisTemplate.delete(refreshTokenKey);
+        }
+    }
+
+    // 토큰 블랙리스트 추가
+    public void blacklistToken(final String token) {
+        redisTemplate.opsForValue().set(BLACKLIST_PREFIX.concat(token), token, getRemainingTokenExpiration(token));
+    }
+
+    // 토큰 블랙리스트 확인
+    public boolean isBlacklisted(final String token) {
+        return redisTemplate.hasKey(BLACKLIST_PREFIX.concat(token));
+    }
+
+    // 토큰 만료 여부 확인
+    public boolean isExpired(final String token) {
+        try {
+            return Jwts.parser()
+                    .verifyWith(this.secretKey)
+                    .build()
+                    .parseSignedClaims(token)
+                    .getPayload()
+                    .getExpiration()
+                    .before(new Date());
+        } catch (ExpiredJwtException ex) {
+            return true;
+        }
+    }
+
+}