@Configuration
public class selectionCorsConfig {
    @Bean
    public CorsWebFilter corsWebFilter(){
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        //配置跨域
        corsConfiguration.addAllowedHeader("*"); //允许所有的头部进行跨域
        corsConfiguration.addAllowedMethod("*"); //允许所有的请求方式进行跨域
        corsConfiguration.addAllowedOrigin("*");  //允许所有来源进行访问跨域
        corsConfiguration.setAllowCredentials(true); //允许携带cookies

        source.registerCorsConfiguration("/**",corsConfiguration); //任意路径都进行跨域配置
        return new CorsWebFilter(source);
    }
}

Access to XMLHttpRequest at ‘http://localhost:88/api/sys/login’ from origin ‘http://localhost:8001’ has been blocked by CORS policy: The ‘Access-Control-Allow-Origin’ header contains multiple values ‘http://localhost:8001, http://localhost:8001’, but only one is allowed.

报错原因：跨域规则设置了多个
解决：查看自己项目中的跨域设置，只用设置一次即可