com.mycompany.springrest.token.JwtUtil.java Source code

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Here is the source code for com.mycompany.springrest.token.JwtUtil.java

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package com.mycompany.springrest.token;

import org.springframework.security.core.userdetails.User;

/**
 *
 * @author ??
 */
public class JwtUtil {

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

    /**
     * Tries to parse specified String as a JWT token. If successful, returns User object with username, id and role prefilled (extracted from token).
     * If unsuccessful (token is invalid or not containing all required user properties), simply returns null.
     * 
     * @param token the JWT token to parse
     * @return the User object extracted from specified token or null if a token is invalid.
     */
    public User parseToken(String token) {
        try {
            Claims body = Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody();

            User u = new User();
            u.setUsername(body.getSubject());
            u.setId(Long.parseLong((String) body.get("userId")));
            u.setRole((String) body.get("role"));

            return u;

        } catch (JwtException | ClassCastException e) {
            return null;
        }
    }

    /**
     * Generates a JWT token containing username as subject, and userId and role as additional claims. These properties are taken from the specified
     * User object. Tokens validity is infinite.
     * 
     * @param u the user for which the token will be generated
     * @return the JWT token
     */
    public String generateToken(User u) {
        Claims claims = Jwts.claims().setSubject(u.getUsername());
        claims.put("userId", u.getId() + "");
        claims.put("role", u.getRole());

        return Jwts.builder().setClaims(claims).signWith(SignatureAlgorithm.HS512, secret).compact();
    }
}