JwtTokenProvider.java

package com.sopromadze.blogapi.security;

import java.util.Date;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.core.Authentication;
import org.springframework.stereotype.Component;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.ExpiredJwtException;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.MalformedJwtException;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.SignatureException;
import io.jsonwebtoken.UnsupportedJwtException;

@Component
public class JwtTokenProvider {
    private static final Logger LOGGER = LoggerFactory.getLogger(JwtTokenProvider.class);

    @Value(value = "${app.jwtSecret}")
    private String jwtSecret;

    @Value(value = "${app.jwtExpirationInMs}")
    private int jwtExpirationInMs;

    public String generateToken(Authentication authentication){
        UserPrincipal userPrincipal = (UserPrincipal) authentication.getPrincipal();

        Date now = new Date();
        Date expiryDate = new Date(now.getTime() + jwtExpirationInMs);

        return Jwts.builder()
                .setSubject(Long.toString(userPrincipal.getId()))
                .setIssuedAt(new Date())
                .setExpiration(expiryDate)
                .signWith(SignatureAlgorithm.HS512, jwtSecret)
                .compact();
    }

    public Long getUserIdFromJWT(String token){
        Claims claims = Jwts.parser()
                .setSigningKey(jwtSecret)
                .parseClaimsJws(token)
                .getBody();

        return Long.valueOf(claims.getSubject());
    }

    public boolean validateToken(String authToken){
        try {
            Jwts.parser().setSigningKey(jwtSecret).parseClaimsJws(authToken);
            return true;
        } catch (SignatureException ex){
            LOGGER.error("Invalid JWT signature");
        } catch (MalformedJwtException ex){
            LOGGER.error("Invalid JWT token");
        } catch (ExpiredJwtException ex){
            LOGGER.error("Expired JWT token");
        } catch (UnsupportedJwtException ex){
            LOGGER.error("Unsupported JWT token");
        } catch (IllegalArgumentException ex){
            LOGGER.error("JWT claims string is empty");
        }
        return false;
    }
}