背景：前后端分离项目，前端vue，后端springboot，本地调试时设置了跨域处理，前端生成的uuid后端从header里面取不到。

解决办法：如下是允许跨域，设置 corsConfiguration.addExposedHeader("uuid"); 放行uuid参数，这样后端就可以获取到了。

@Configuration
public class CorsConfig {

    private CorsConfiguration buildConfig() {
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOrigin("*");
        corsConfiguration.addAllowedHeader("*");
        corsConfiguration.addAllowedMethod("*");
        corsConfiguration.setMaxAge(3600L);
        corsConfiguration.setAllowCredentials(true);
        return corsConfiguration;
    }

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration corsConfiguration = buildConfig();
        corsConfiguration.addExposedHeader("uuid");
        source.registerCorsConfiguration("/**", corsConfiguration);
        return new CorsFilter(source);
    }
}