/** SecurityConfig extends WebSecurityConfigurerAdapter, część metody configure(http) **/

//        CustomUsernamePasswordAuthenticationFilter customUsernamePasswordAuthenticationFilter = new CustomUsernamePasswordAuthenticationFilter();
//        customUsernamePasswordAuthenticationFilter.setAuthenticationManager(authenticationManager());
//        http.addFilterAt(customUsernamePasswordAuthenticationFilter, UsernamePasswordAuthenticationFilter.class);
        http.formLogin()
                .successHandler(authenticationSuccessHandler)
                .failureHandler(authenticationFailureHandler);

public class CustomUsernamePasswordAuthenticationFilter extends UsernamePasswordAuthenticationFilter {
    @Override
    protected String obtainUsername(HttpServletRequest request) {
        return request.getHeader("username");
    }

    @Override
    protected String obtainPassword(HttpServletRequest request) {
        return request.getHeader("password");
    }

    @Override
    @Autowired
    public void setAuthenticationManager(AuthenticationManager authenticationManager) {
        super.setAuthenticationManager(authenticationManager);
    }
}