使用Spring Security和JWT来进行身份验证和授权（二）

@Component
public class JwtTokenUtil {

    private String secret = "my-secret-key";

    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>();
        return doGenerateToken(claims, userDetails.getUsername());
    }

    private String doGenerateToken(Map<String, Object> claims, String subject) {
        long expirationTimeInMs = 3600000; // 1 hour
        Date expirationTime = new Date(System.currentTimeMillis() + expirationTimeInMs);

        return Jwts.builder().setClaims(claims).setSubject(subject).setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(expirationTime)
                .signWith(SignatureAlgorithm.HS512, secret).compact();
    }

    public String getUsernameFromToken(String token) {
        return Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody().getSubject();
    }

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

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

    private Date getExpirationDateFromToken(String token) {
        return Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody().getExpiration();
    }

}