springbootjwt工具类

以下是一个简单的Spring Boot JWT工具类的示例，它使用了Java JWT和JJWT库来实现JWT的生成和验证：

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

@Component
public class JwtUtil {

    private static final long JWT_TOKEN_VALIDITY = 5 * 60 * 60;

    @Value("${jwt.secret}")
    private String secret;

    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) {
        Date now = new Date();
        Date expirationDate = new Date(now.getTime() + JWT_TOKEN_VALIDITY * 1000);

        return Jwts.builder()
                .setClaims(claims)
                .setSubject(subject)
                .setIssuedAt(now)
                .setExpiration(expirationDate)
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }

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

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

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

    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.parser().setSigningKey(secret).parseClaimsJws(token).getBody();
    }

    private Boolean isTokenExpired(String token) {
        final Date expiration = extractExpiration(token);
        return expiration.before(new Date());
    }
}

该工具类包含了生成JWT令牌和验证JWT令牌的方法。在生成JWT令牌时，它使用了传递的用户详细信息和当前时间来创建一个JWT令牌。在验证JWT令牌时，它使用了传递的JWT令牌和用户详细信息来验证JWT令牌是否有效。