public class JwtUtils {

    private final Key key;

    public JwtUtils(String secret) {
        this.key = Keys.hmacShaKeyFor(secret.getBytes());
    }

    /**
     * 토큰의 payload에 유저의 Id와 name 을 삽입
     * @param userId 유저의 id
     * @param name 유저의 name
     * @rturn jwt token
     * */
    public String createToken(Long userId, String name) {
        String token = Jwts.builder()
                .claim("userId", userId)
                .claim("name", name)
                .signWith(key, SignatureAlgorithm.HS256)
                .compact();

        return token;
    }

    /**
     * token 으로 부터 payload 를 추출하는 메서드
     * @param token JwtUtils 로부터 만들어진 토큰
     * @return token 의 payload(=claims)
     * */
    public Claims getClaims(String token) {
        return Jwts.parser()
                .setSigningKey(key)
                .parseClaimsJws(token)  //JWS = Signature 가 포함된 내용
                .getBody();
    }
}

public class JwtAuthenticationFilter extends BasicAuthenticationFilter {

    private JwtUtils jwtUtils;

    public JwtAuthenticationFilter(AuthenticationManager authenticationManager, JwtUtils jwtUtils) {
        super(authenticationManager);
        this.jwtUtils = jwtUtils;
    }

    /**
     * SecurityContext 에 Authentication 객체 세팅.
     * */
    @Override
    protected void doFilterInternal(HttpServletRequest request,
                                    HttpServletResponse response,
                                    FilterChain chain) throws IOException, ServletException {

        Authentication authentication = getAuthentication(request);
        if (authentication != null) {
            SecurityContext context = SecurityContextHolder.getContext();
            context.setAuthentication(authentication);
        }
        chain.doFilter(request, response);
    }

    /**
     * 헤더의 Authorization로부터 토큰을 가져와 사용자의 정보를 담을 Authentication 객체로 변환
     * */
    private Authentication getAuthentication(HttpServletRequest request) {
        String token = request.getHeader("Authorization");
        if (Strings.isEmpty(token)) {
            return null;
        }

        Claims claims = jwtUtils.getClaims(token.substring("Bearer ".length()));

        return new UsernamePasswordAuthenticationToken(claims, null);
    }
}

@Configuration
@EnableWebSecurity
public class SecurityJavaConfig extends WebSecurityConfigurerAdapter {

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

    @Override
    protected void configure(HttpSecurity http) throws Exception {

        http.formLogin().disable()
                .csrf().disable()
                .cors().disable()
                .headers().frameOptions().disable()
        ;
			
        //JwtAuthentication필터 추가
        http.addFilter(jwtAuthenticationFilter())
                .sessionManagement()
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
        ;
    }

    @Bean
    public BCryptPasswordEncoder encoder() {
        return new BCryptPasswordEncoder();
    }

    @Bean
    public JwtUtils jwtUtils() {
        return new JwtUtils(secret);
    }

    @Bean
    public JwtAuthenticationFilter jwtAuthenticationFilter() throws Exception {
        return new JwtAuthenticationFilter(authenticationManager(), jwtUtils());
    }
}

@RestController
public class ReviewController {

    @Autowired
    private JwtUtils jwtUtils;
    
    @PostMapping("/test")
    public ResponseEntity auth(Authentication auth) throws URISyntaxException {

        if(auth == null){
            throw new TokenNotExistedException();
        }
        
        return ResponseEntity.ok().body("success");
    }
    
    @PostMapping("/getToken")
    public String getToken(@RequestBody @RequestParam String email,
                           @RequestBody @RequestParam String password){
        
        if(email.equals("test@example.com") && password.equals("1234")){
            Long id = 1L;
            String name = "tester";
            return jwtUtils.createToken(id,name);
        }
        return null;
    }

}

@ControllerAdvice
public class ReviewErrorAdvice {

    @ResponseBody
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ExceptionHandler(TokenNotExistedException.class)
    public String tokenNotExisted(){
        return "토큰이 존재하지 않습니다.";
    }

    @ResponseBody
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ExceptionHandler(SignatureException.class)
    public String NotValidToken(){
        return "유효하지 않는 토큰입니다.";
    }
}