Why can't springMVC's ViewControllerRegistry.addViewController intercept the root directory?

spring intercepts localhost:8080/1 to intercept my chat page, but not to the root directory. Go back to the default index page;

console has such important several lines of log output

2018-06-04 15:46:03.601  INFO 15836 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/login] onto handler of type [class org.springframework.web.servlet.mvc.ParameterizableViewController]
2018-06-04 15:46:03.601  INFO 15836 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Root mapping to handler of type [class org.springframework.web.servlet.mvc.ParameterizableViewController]
2018-06-04 15:46:03.601  INFO 15836 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/1] onto handler of type [class org.springframework.web.servlet.mvc.ParameterizableViewController]
2018-06-04 15:46:03.663  INFO 15836 --- [  restartedMain] o.s.b.a.w.s.WelcomePageHandlerMapping    : Adding welcome page template: index

configuration of springMVC

@Configuration
public class WebMvcConfg implements WebMvcConfigurer {
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/login").setViewName("/login");
        registry.addViewController("/").setViewName("/chat");
        registry.addViewController("/1").setViewName("/chat");
    }
}

configuration of spring security

@Configuration
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

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

        http.authorizeRequests()
                .anyRequest()
                .authenticated()
                .and()
                //
                .formLogin()
                //
                .loginPage("/login")
                //
                .defaultSuccessUrl("/")
                .permitAll()
                .and()
                //
                .logout()
                .permitAll();
    }
   }