SpringBoot无法加载static下的静态资源

直接上代码
第一步：其中重写 addResourceHandlers 方法很重要

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
    @Bean //将组件注册在容器
    public WebMvcConfigurer webMvcConfigurerAdapter(){
        WebMvcConfigurer adapter = new WebMvcConfigurer() {
            @Override
            public void addViewControllers(ViewControllerRegistry registry) {
                registry.addViewController("/").setViewName("index");
                registry.addViewController("/login.html").setViewName("index");
            }
            
            //注册拦截器
            @Override
            public void addInterceptors(InterceptorRegistry registry) {
                registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
                        .excludePathPatterns("/login.html", "/user/login", "/","/static/**","/**/*.css");
            }                                                               //就是不能放行css，我也很纳闷
            
            //放行资源必须配置的
            @Override
            public void addResourceHandlers(ResourceHandlerRegistry registry) {
                registry.addResourceHandler("/static/**")
                        .addResourceLocations("classpath:/static/");
            }
        };
        
        return adapter;
    }
}

第二步： css引入资源的前面加上/static

th:href="@{/static/a/css/b.css}"