diff --git a/src/main/java/co/jp/app/service/JwtService.java b/src/main/java/co/jp/app/service/JwtService.java
new file mode 100644
index 0000000..ff0cd74
--- /dev/null
+++ b/src/main/java/co/jp/app/service/JwtService.java
@@ -0,0 +1,102 @@
+package co.jp.app.service;
+
+import io.jsonwebtoken.*;
+import io.jsonwebtoken.security.Keys;
+import java.util.function.Function;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.stereotype.Service;
+
+import java.security.Key;
+import java.util.Base64;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Map;
+
+@Service
+public class JwtService {
+
+    private static final Logger logger = LoggerFactory.getLogger(JwtService.class);
+    //log
+
+    @Value("${jwt.secret}")
+    private String secretKey;
+
+    @Value("${jwt.token-expiration-ms}")
+    private long tokenExpirationMs;
+
+    private Key getSignKey() {
+        byte[] keyBytes = Base64.getDecoder().decode(secretKey);
+        return Keys.hmacShaKeyFor(keyBytes);
+    }
+
+    public String extractUsername(String token) {
+        try {
+            return extractClaim(token, Claims::getSubject);
+        } catch (ExpiredJwtException e) {
+            logger.warn("JWT token is expired when extracting username: {}", e.getMessage());
+            return e.getClaims().getSubject();
+        } catch (MalformedJwtException | SignatureException | UnsupportedJwtException | IllegalArgumentException e) {
+            logger.error("Invalid JWT token when extracting username: {}", e.getMessage());
+            return null;
+        }
+    }
+
+    public <T> T extractClaim(String token, Function<Claims, T> claimsResolver) {
+        final Claims claims = extractAllClaims(token);
+        return claimsResolver.apply(claims);
+    }
+
+    private Claims extractAllClaims(String token) {
+        return Jwts
+                .parserBuilder()
+                .setSigningKey(getSignKey())
+                .build()
+                .parseClaimsJws(token)
+                .getBody();
+    }
+
+    public String generateToken(UserDetails userDetails) {
+        Map<String, Object> claims = new HashMap<>();
+        return createToken(claims, userDetails.getUsername());
+    }
+
+    private String createToken(Map<String, Object> claims, String subject) {
+        return Jwts.builder()
+                .setClaims(claims)
+                .setSubject(subject)
+                .setIssuedAt(new Date(System.currentTimeMillis()))
+                .setExpiration(new Date(System.currentTimeMillis() + tokenExpirationMs)) // 使用配置的过期时间
+                .signWith(getSignKey(), SignatureAlgorithm.HS256)
+                .compact();
+    }
+
+    public boolean isTokenValid(String token, UserDetails userDetails) {
+        try {
+            final String username = extractUsername(token);
+            if (username == null) {
+                return false;
+            }
+
+            return (username.equals(userDetails.getUsername()) && !isTokenActuallyExpired(token));
+        } catch (ExpiredJwtException e) {
+            logger.warn("Token validation failed: Expired JWT - {}", e.getMessage());
+            return false;
+        } catch (MalformedJwtException | SignatureException | UnsupportedJwtException | IllegalArgumentException e) {
+            // 这些是更严重的token结构或签名问题
+            logger.error("Token validation failed: Invalid JWT (format, signature, etc.) - {}", e.getMessage());
+            return false;
+        }
+    }
+
+    private boolean isTokenActuallyExpired(String token) {
+        return extractExpiration(token).before(new Date());
+    }
+
+    private Date extractExpiration(String token) {
+        return extractClaim(token, Claims::getExpiration);
+    }
+}