springboot访问后端静态资源404问题

@Configuration
public class CorsConfig implements WebMvcConfigurer {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**").allowedOrigins("*")
                .allowedMethods("GET", "HEAD", "POST","PUT", "DELETE", "OPTIONS")
                .allowCredentials(true).maxAge(3600);
    }
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        //开放static,templates,public 目录 但是请求时候需要加上对应的前缀,比如我访问static下的资源/static/xxxx/xx.js
        registry.addResourceHandler("/static/**","/templates/**","/public/**")
                .addResourceLocations("classpath:/static/","classpath:/templates/","classpath:/public/");

    }

}

spring:
  mvc:
    static-path-pattern: /res/** #静态资源访问前缀为res

---
spring:
  resources:
    static-locations: [classpath:/res/] #在类路径的res文件夹下的静态资源才能被访问到

public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String username;
    private String password;

    // 省略 getter 和 setter 方法
}