$.ajax({
        url:httpUrl,
        type: 'get',
        data: {},
        beforeSend: function(request){
            request.setRequestHeader("token", "xxxx");
        },
        dataType: 'json',
        success: function(data){
            console.log(data);
        },
        error: function(error){
            console.log(error)
        }
    });

the above is front-end request processing.
the following is the backend (java) processing:

@Configuration
    public class CorsConf {
        @Bean
        public CorsFilter corsFilter() {
            UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
            CorsConfiguration corsConfiguration = new CorsConfiguration();
            corsConfiguration.addAllowedOrigin("*");
            corsConfiguration.addAllowedHeader("*");
            corsConfiguration.addAllowedMethod("*");
            source.registerCorsConfiguration("/**", corsConfiguration);
            return new CorsFilter(source);
        }
    }

get the xhr object, call the setHeader method
of xhr or the framework is generally encapsulated. Just pass header directly

setting header token of ajax

axios:
axios.interceptors.request.use(config => {
   config.headers = {
      'X-token': token
   }
  
  return config
}, err => {
  return Promise.reject(err)
})
 so that token can be included in each request header.