import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.security.Keys;
import java.util.HashMap;
public class TestJwt {
    public static void main(String[] args) {
        try {
            byte[] key = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa".getBytes();
            HashMap<String, Object> claims = new HashMap<>();
            claims.put("userId", 1L);
            String token = Jwts.builder().claims(claims).signWith(Keys.hmacShaKeyFor(key)).compact();
            Long parsed = Jwts.parser().verifyWith(Keys.hmacShaKeyFor(key)).build().parseSignedClaims(token).getPayload().get("userId", Long.class);
            System.out.println("Parsed: " + parsed);
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
}