SpringCloudGateway手动编写路由规则对请求进行转发

这篇文章主要是提供一种转发路由的代码实现方式，之前说的gateway都是使用配置文件来对请求进行路由，这样虽然很简单，但是不够灵活，如果后端对应很多服务实例，网关想要根据自己的规则来转发请求，比如编写不同的负载均衡策略，做一些特别的权重，以及在运行过程中动态的变更转发地址，这些用配置文件来做都不够灵活，没法自由的定义规则。

涉及的gateway版本

org.springframework.cloudspring-cloud-starter-gateway2.1.4.RELEASE

主要实现过程还是实现GatewayFilter接口，获取到要指定的IP地址与端口，然后组装成URI与Route，最后转发出去

importcn.hutool.core.util.ObjectUtil;importcn.hutool.core.util.StrUtil;importcom.ecwid.consul.v1.health.model.HealthService;importlombok.extern.slf4j.Slf4j;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.beans.factory.annotation.Value;importorg.springframework.cloud.gateway.filter.GatewayFilter;importorg.springframework.cloud.gateway.filter.GatewayFilterChain;importorg.springframework.cloud.gateway.route.Route;importorg.springframework.core.Ordered;importorg.springframework.http.server.reactive.ServerHttpResponse;importorg.springframework.web.server.ServerWebExchange;importorg.springframework.web.util.UriComponentsBuilder;importjava.net.URI;importjava.util.List;importjava.util.Optional;importreactor.core.publisher.Mono;importstatic org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR;/**

* 转发路由，通过负载均衡对后端服务进行访问

*

*/@Slf4jpublicclassRouteFilterimplementsGatewayFilter,Ordered{    @AutowiredprivateRedisUtilredisUtil;    @AutowiredprivateLoadBalanceHandlerloadBalance;    @OverridepublicMonofilter(ServerWebExchangeexchange,GatewayFilterChainchain) {ServerHttpResponseresponse = exchange.getResponse();//获取原来的请求路径StringrequestPath = exchange.getAttribute(FilterDict.SYSTEM_REQUEST_PATH);//randomSelectInstance方法会获取到一个"ip:port"这样结构的字符串StringinstanceInfo = loadBalance.randomSelectInstance();//如果没有服务，则直接返回报错if(StrUtil.isEmpty(instanceInfo)) {returnresponse.writeWith(Mono.just(GateWayFilterUtils.writeData(exchange,RecoError.GEN_SERVER_BUSY)));        }//用于测试负载均衡算法对IP分配是否均衡//        redisUtil.zIncrementScore("test:gateway:load:ip",instanceInfo,1);//分割地址中IP和端口String[] serviceAddress = instanceInfo.split(StrUtil.COLON);StringrequestSchema = exchange.getRequest().getURI().getScheme();//拼接URL的数据assertObjectUtil.isNotNull(requestPath);URIuri =UriComponentsBuilder.                newInstance().scheme(requestSchema).                host(serviceAddress[0].trim()).port(Integer.parseInt(serviceAddress[1].trim()))                .path(requestPath).query(exchange.getRequest().getURI().getRawQuery()).build(true)                .toUri();//将拼接好的URL装入新的exchangeServerWebExchangemutateExchange = exchange.mutate().request(builder -> builder.uri(uri).build()).build();Optional route =Optional.of(exchange.getAttribute(GATEWAY_ROUTE_ATTR));RoutenewRoute =Route.async()                .asyncPredicate(route.get().getPredicate())                .filters(route.get().getFilters())                .id(route.get().getId())                .order(route.get().getOrder())                .uri(uri).build();        mutateExchange.getAttributes().put(GATEWAY_ROUTE_ATTR, newRoute);        mutateExchange.getAttributes().put(FilterDict.SYSTEM_APP_IP_ADDR, serviceAddress[0]);returnchain.filter(mutateExchange);    }    @Overridepublicint getOrder() {returnFilterDict.SYSTEM_FILTER_ORDER+4;    }}

单独编写路由filter以后，还需要引入才能执行，在全局配置中倒入bean，最后启动就可以执行了

importorg.springframework.beans.factory.annotation.Value;importorg.springframework.cloud.gateway.filter.ratelimit.RedisRateLimiter;importorg.springframework.cloud.gateway.route.RouteLocator;importorg.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;importorg.springframework.context.annotation.Bean;importorg.springframework.context.annotation.Configuration;importlombok.extern.slf4j.Slf4j;importjava.time.Duration;/** * 全局过滤器配置加载 * *@author:wcy */@Slf4j@ConfigurationpublicclassGlobalFilterConfigure{//用于设置路由的@BeanpublicRouteFilter routeFilter(){returnnew RouteFilter();    }/**

    * 将所有自定义的filter加载进来

    */@BeanpublicRouteLocator customerRouteLocator(RouteLocatorBuilder builder, RedisRateLimiter redisRateLimiter) {returnbuilder.routes()                .route(r -> r.path(FilterDict.GATEWAY_BASE_INTERCEPT_URL)//将自定义的filter加载进来.filters(f -> f.filters(routeFilter())//请求大小.setRequestSize(requestLimitSize)//请求限流,目前使用请求IP,以后可以扩展使用其他限定组合//                                .filter(rateLimitByIpGatewayFilter()))                        .uri("http://127.0.0.1:"+ servicePort +"/actuator/health")                        .order(FilterDict.SYSTEM_FILTER_ORDER)                        .id(FilterDict.GATEWAY_ROUTE_NAME)                ).build();    }}