Configuring swagger for spring boot, spring security JWT

Question

I'm trying to develop Spring Boot REST API and securing it using Spring security with JWT.

I'm using swagger for documenting my endpoints, but I can't have access to file swagger.json.

Swagger get my this error:

401 : {"timestamp":1491816380377,"status":401,"error":"Unauthorized",
"message":"Authentication Failed: No JWT token found in request headers",
"path":"/api/swagger.json"} 
http://localhost:8080/api/swagger.json

This is my WebSecurityConfig:

@Configuration
@EnableWebSecurity
@EnableAutoConfiguration
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private JwtAuthenticationEntryPoint unauthorizedHandler;

    @Autowired
    private JwtAuthenticationProvider authenticationProvider;

    @Bean
    @Override
    public AuthenticationManager authenticationManager() throws Exception {

        return new ProviderManager(Arrays.asList(authenticationProvider));
    }

    @Bean
    public JwtAuthenticationTokenFilter authenticationTokenFilterBean() throws Exception {
        JwtAuthenticationTokenFilter authenticationTokenFilter = new JwtAuthenticationTokenFilter();
        authenticationTokenFilter.setAuthenticationManager(authenticationManager());
        authenticationTokenFilter.setAuthenticationSuccessHandler(new JwtAuthenticationSuccessHandler());
        return authenticationTokenFilter;
    }

    @Override
    protected void configure(HttpSecurity httpSecurity) throws Exception {
        httpSecurity.csrf().disable().authorizeRequests()
                .antMatchers("/swagger/**").permitAll()
                .antMatchers("/api/swagger.json").permitAll()
                .antMatchers(HttpMethod.POST, "/login").permitAll()
                .anyRequest().authenticated();

        httpSecurity
                .addFilterBefore(authenticationTokenFilterBean(), UsernamePasswordAuthenticationFilter.class);
    }
}

but this rule doesn't work:

.antMatchers("/api/swagger.json").permitAll()