如何在Spring Boot中从旧的token生成新的JWT token？

<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.9.1</version>
</dependency>

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

import java.util.Date;

public class TokenUtil {
    private static final String SECRET_KEY = "your-secret-key"; // 设置JWT的密钥

    public static String generateJwtToken(String oldToken) {
        Claims claims = Jwts.parser()
                .setSigningKey(SECRET_KEY)
                .parseClaimsJws(oldToken)
                .getBody();

        // 从旧的token中获取需要的信息
        String username = claims.getSubject();
        Date expirationDate = claims.getExpiration();

        // 构建新的JWT token
        String newToken = Jwts.builder()
                .setSubject(username)
                .setExpiration(expirationDate)
                .signWith(SignatureAlgorithm.HS512, SECRET_KEY)
                .compact();

        return newToken;
    }
}

String oldToken = "your-old-token";
String newToken = TokenUtil.generateJwtToken(oldToken);