2311061234/src/main/java/com/vibevault/security/JwtService.java

package com.vibevault.security;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.ExpiredJwtException;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.MalformedJwtException;
import io.jsonwebtoken.security.Keys;
import io.jsonwebtoken.security.SecurityException;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import com.vibevault.model.User;

import javax.crypto.SecretKey;
import java.nio.charset.StandardCharsets;
import java.util.Date;


/**
 * JWT 服务
 * 
 * 提供 JWT token 的生成、验证和解析功能
 */
@Service
public class JwtService {

    @Value("${jwt.secret:your-secret-key-here-should-be-at-least-256-bits-long-for-hs256}")
    private String secret;

    @Value("${jwt.expiration:86400000}")
    private long expiration; // 默认 24 小时

    /**
     * 为用户生成 JWT token
     */
    public String generateToken(String username) {
        Date now = new Date();
        Date expiryDate = new Date(now.getTime() + expiration);
        
        return Jwts.builder()
                .setSubject(username)
                .setIssuedAt(now)
                .setExpiration(expiryDate)
                .signWith(getSigningKey())
                .compact();
    }

    /**
     * 从 token 中提取用户名
     */
    public String extractUsername(String token) {
        Claims claims = extractAllClaims(token);
        return claims.getSubject();
    }

    /**
     * 验证 token 是否有效
     */
    public boolean isTokenValid(String token, User user) {
        try {
            String username = extractUsername(token);
            return username.equals(user.getUsername()) && !isTokenExpired(token);
        } catch (Exception e) {
            return false;
        }
    }

    /**
     * 验证 token 是否有效
     */
    public boolean isTokenValid(String token) {
        try {
            extractAllClaims(token);
            return !isTokenExpired(token);
        } catch (Exception e) {
            return false;
        }
    }

    /**
     * 检查 token 是否过期
     */
    private boolean isTokenExpired(String token) {
        Date expirationDate = extractExpiration(token);
        return expirationDate.before(new Date());
    }

    /**
     * 提取 token 的过期时间
     */
    private Date extractExpiration(String token) {
        Claims claims = extractAllClaims(token);
        return claims.getExpiration();
    }

    /**
     * 从 token 中提取所有声明
     */
    private Claims extractAllClaims(String token) {
        return Jwts.parserBuilder()
                .setSigningKey(getSigningKey())
                .build()
                .parseClaimsJws(token)
                .getBody();
    }

    /**
     * 获取签名密钥
     */
    private SecretKey getSigningKey() {
        return Keys.hmacShaKeyFor(secret.getBytes(StandardCharsets.UTF_8));
    }
    
    /**
     * 验证 token 签名和格式
     */
    public boolean validateToken(String token) {
        try {
            Jwts.parserBuilder()
                .setSigningKey(getSigningKey())
                .build()
                .parseClaimsJws(token);
            return true;
        } catch (SecurityException e) {
            System.out.println("无效的 JWT 签名");
        } catch (MalformedJwtException e) {
            System.out.println("无效的 JWT token");
        } catch (ExpiredJwtException e) {
            System.out.println("JWT token 已过期");
        } catch (IllegalArgumentException e) {
            System.out.println("JWT token 为空或格式错误");
        }
        return false;
    }
}