SpringCloud gateway 跨域

要在Spring Cloud Gateway中实现跨域，可以通过添加一个自定义的GlobalFilter来实现。以下是一个简单的实现示例：

@Component
public class CorsFilter implements GlobalFilter, Ordered {

    private static final String ALLOWED_HEADERS = "x-requested-with, authorization, Content-Type, Authorization, credential, X-XSRF-TOKEN";
    private static final String ALLOWED_METHODS = "GET, PUT, POST, DELETE, OPTIONS";
    private static final String ALLOWED_ORIGIN = "*";
    private static final String MAX_AGE = "3600";

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        if (CorsUtils.isCorsRequest(request)) {
            HttpHeaders headers = request.getHeaders();
            ServerHttpResponse response = exchange.getResponse();
            HttpMethod requestMethod = headers.getAccessControlRequestMethod();
            HttpHeaders responseHeaders = response.getHeaders();
            if (requestMethod != null) {
                responseHeaders.add(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, ALLOWED_ORIGIN);
                responseHeaders.addAll(HttpHeaders.ACCESS_CONTROL_ALLOW_HEADERS, ALLOWED_HEADERS);
                responseHeaders.add(HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS, ALLOWED_METHODS);
                responseHeaders.add(HttpHeaders.ACCESS_CONTROL_MAX_AGE, MAX_AGE);
                responseHeaders.add(HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS, "true");
                if (request.getMethod() == HttpMethod.OPTIONS) {
                    response.setStatusCode(HttpStatus.OK);
                    return Mono.empty();
                }
            }
        }
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
        return Ordered.HIGHEST_PRECEDENCE;
    }
}

这个过滤器会检查请求是否为跨域请求，如果是，则添加必需的响应头以允许跨域请求。这里的ALLOWED_HEADERS、ALLOWED_METHODS、ALLOWED_ORIGIN、MAX_AGE和ALLOWED_ORIGIN都可以根据实际需要进行修改。最后，将这个过滤器添加到Spring Cloud Gateway的过滤器链中即可实现跨域。