由于gateway使用的是webflux，而不是springmvc，所以需要先关闭webflux的cors，再从gateway的filter里边设置cors就行了。

首先gateway版本

 <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
            <version>2.0.1.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-gateway-core</artifactId>
            <version>2.0.1.RELEASE</version>
        </dependency>

** ps: 2.0.1.RELEASE 以下的版本有bug，Conten-Type 如果请求没有设置的话，会报空指针NPE 问题。
官方在2.0.1的版本修复了**

/**
 * @ClassName CorsConfig
 * @Author dlh
 * @Date 2019/5/7 0007 下午 4:55
 * @Version 1.0
 **/
@Configuration
public class CorsConfig {
    @Bean
    public CorsWebFilter corsFilter() {
        CorsConfiguration config = new CorsConfiguration();
        config.addAllowedMethod("*");
        config.addAllowedOrigin("*");
        config.addAllowedHeader("*");

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource(new PathPatternParser());
        source.registerCorsConfiguration("/**", config);

        return new CorsWebFilter(source);
    }
}

网关之前设置的是全局filter

/**
 * @ClassName CrossOriginFilter
 * @Author dlh
 * @Date 2019/5/7 0007 下午 4:50
 * @Version 1.0
 **/
@Component
public class CrossOriginFilter implements GlobalFilter, Ordered {

    private static Logger logger = LoggerFactory.getLogger(CrossOriginFilter.class);

    private static final String ALL = "*";
    private static final String MAX_AGE = "18000L";


    @Override
    public Mono<Void> filter(ServerWebExchange serverWebExchange, GatewayFilterChain gatewayFilterChain) {
        ServerHttpRequest request = serverWebExchange.getRequest();
        ServerHttpResponse response = serverWebExchange.getResponse();
        HttpHeaders headers = response.getHeaders();
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, "*");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS, "POST, GET, PUT, OPTIONS, DELETE, PATCH");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS, "true");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_HEADERS, "*");
        headers.add(HttpHeaders.ACCESS_CONTROL_EXPOSE_HEADERS, ALL);
        headers.add(HttpHeaders.ACCESS_CONTROL_MAX_AGE, MAX_AGE);
        if (request.getMethod() == HttpMethod.OPTIONS) {
            response.setStatusCode(HttpStatus.OK);
            return Mono.empty();
        }
        return gatewayFilterChain.filter(serverWebExchange);
    }

    @Override
    public int getOrder() {
        return -300;
    }
}

转载 https://www.jianshu.com/p/a46e62f9ad1c