（原因：不允许有多个 ‘Access-Control-Allow-Origin‘ CORS 头）

Dear 丶 2021-09-18 06:24 362阅读 0赞

前后端分离就会碰到跨域问题，原本我们在后端采用 CORS 解决，现在利用网关，可以放在网关解决。

版本：  
spring-cloud：Hoxton.SR3

一共两个文件

CorsConfiguration.java

/** * 配置跨域 */
    @Configuration
    public class CorsConfiguration { 
    
        @Bean
        public CorsResponseHeaderFilter corsResponseHeaderFilter() { 
            return new CorsResponseHeaderFilter();
        }
    
        @Bean
        public CorsWebFilter corsWebFilter() { 
            UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
            CorsConfiguration corsConfiguration = new CorsConfiguration();
    
            corsConfiguration.addAllowedHeader("*");
            corsConfiguration.addAllowedMethod("*");
            corsConfiguration.addAllowedOrigin("*");
            corsConfiguration.setAllowCredentials(true);
            corsConfiguration.setMaxAge(600L);
    
            source.registerCorsConfiguration("/**", corsConfiguration);
            return new CorsWebFilter(source);
        }
    }

CorsResponseHeaderFilter.java

/** * 跨域请求头重复处理过滤器 */
    public class CorsResponseHeaderFilter implements GlobalFilter, Ordered { 
        @Override
        public int getOrder() { 
            // 指定此过滤器位于NettyWriteResponseFilter之后
            // 即待处理完响应体后接着处理响应头
            return NettyWriteResponseFilter.WRITE_RESPONSE_FILTER_ORDER + 1;
        }
    
        @Override
        @SuppressWarnings("serial")
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { 
            return chain.filter(exchange).then(Mono.defer(() -> { 
                exchange.getResponse().getHeaders().entrySet().stream()
                        .filter(kv -> (kv.getValue() != null && kv.getValue().size() > 1))
                        .filter(kv -> (kv.getKey().equals(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN)
                                || kv.getKey().equals(HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS)))
                        .forEach(kv ->
                        { 
                            kv.setValue(new ArrayList<String>() { { 
                                add(kv.getValue().get(0));
                            }});
                        });
    
                return chain.filter(exchange);
            }));
        }
    }