@Component
public class AuthProvider implements AuthenticationProvider
{

    @Autowired
    private UserService userService;

    @Autowired
    private PasswordEncoder passwordEncoder;

    @Override
    public Authentication authenticate(Authentication authentication) throws AuthenticationException
    {
        String username = authentication.getName();
        String password = (String) authentication.getCredentials();

        User user = (User) userService.loadUserByUsername(username);

        if (user != null && user.getUsername().equals(username))
        {
            if (!passwordEncoder.matches(password, user.getPassword()))
            {
                throw new BadCredentialsException("Wrong password!");
            }

            Collection<? extends GrantedAuthority> authorities = user.getAuthorities();

            return new UsernamePasswordAuthenticationToken(user, password, authorities);
        }

        throw new BadCredentialsException("Username not found");
    }

    @Override
    public boolean supports(Class<?> aClass)
    {
        return true;
    }
}