这篇文章将为大家详细讲解有关springcloud gateway怎么实现路由和负载均衡，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。
简介：
gateway主要是做路由 负载，过滤 主要是替代zuul 1.x 性能比zuul好 zuul是基于
Servlet ，gateway是基于spring-webflux 用的netty+reactor
yml文件
实现路由 负载 的配置 亲自测试
spring: application: name: xgyx_gateway cloud: discovery: locator: enabled: true gateway: routes: - id: a #随便定义不重复就好 uri: lb://xgyx-welfareservice-x #服务名称 predicates: - Path=/m@Deprecatedpublic class LoadBalancerClientFilter implements GlobalFilter, Ordered { public static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10100; private static final Log log = LogFactory.getLog(LoadBalancerClientFilter.class); protected final LoadBalancerClient loadBalancer; private LoadBalancerProperties properties; public LoadBalancerClientFilter(LoadBalancerClient loadBalancer, LoadBalancerProperties properties) { this.loadBalancer = loadBalancer; this.properties = properties; } public int getOrder() { return 10100; } public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { URI url = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR); String schemePrefix = (String)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR); if (url != null && ("lb".equals(url.getScheme()) || "lb".equals(schemePrefix))) { ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url); if (log.isTraceEnabled()) { log.trace("LoadBalancerClientFilter url before: " + url); } ServiceInstance instance = this.choose(exchange); if (instance == null) { throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost()); } else { URI uri = exchange.getRequest().getURI(); String overrideScheme = instance.isSecure() ? "https" : "http"; if (schemePrefix != null) { overrideScheme = url.getScheme(); } URI requestUrl = this.loadBalancer.reconstructURI(new DelegatingServiceInstance(instance, overrideScheme), uri); if (log.isTraceEnabled()) { log.trace("LoadBalancerClientFilter url chosen: " + requestUrl); } exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl); return chain.filter(exchange); } } else { return chain.filter(exchange); } } protected ServiceInstance choose(ServerWebExchange exchange) { return this.loadBalancer.choose(((URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR)).getHost()); }}说明：默认使用该类，可通过下述方法使用ReactiveLoadbalancerClientFilter
"You already have RibbonLoadBalancerClient on your classpath. It will be used by default.
As Spring Cloud Ribbon is in maintenance mode. We recommend switching to " + BlockingLoadBalancerClient.class.getSimpleName() + " instead.
In order to use it, set the value of `spring.cloud.loadbalancer.ribbon.enabled` to `false`
or remove spring-cloud-starter-netflix-ribbon from your project."
ReactiveLoadBalancerClientFilter：负载均衡拦截器
public class ReactiveLoadBalancerClientFilter implements GlobalFilter, Ordered { private static final Log log = LogFactory.getLog(ReactiveLoadBalancerClientFilter.class); private static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10150; private final LoadBalancerClientFactory clientFactory; private LoadBalancerProperties properties; public ReactiveLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties properties) { this.clientFactory = clientFactory; this.properties = properties; } public int getOrder() { return 10150; } public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { URI url = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR); String schemePrefix = (String)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR); if (url != null && ("lb".equals(url.getScheme()) || "lb".equals(schemePrefix))) { //url不为null且协议为lb，或者url以lb开头 ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url); if (log.isTraceEnabled()) { log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() + " url before: " + url); } return this.choose(exchange).doOnNext((response) -> { //获取ServiceInstance实例，进行一些处理 if (!response.hasServer()) { //如果没有serviceInstance，直接抛出异常 throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost()); } else { //如果有serviceInstance，进行相关处理 URI uri = exchange.getRequest().getURI(); String overrideScheme = null; if (schemePrefix != null) { overrideScheme = url.getScheme(); } DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance((ServiceInstance)response.getServer(), overrideScheme); URI requestUrl = LoadBalancerUriTools.reconstructURI(serviceInstance, uri); if (log.isTraceEnabled()) { log.trace("LoadBalancerClientFilter url chosen: " + requestUrl); } exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl); } }).then(chain.filter(exchange)); } else { return chain.filter(exchange); //如果获取不到serviceInstance，直接进行后续过滤 } } private Mono<Response<ServiceInstance>> choose(ServerWebExchange exchange) { URI uri = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR); ReactorLoadBalancer<ServiceInstance> loadBalancer = (ReactorLoadBalancer)this.clientFactory.getInstance(uri.getHost(), ReactorLoadBalancer.class, new Class[]{ServiceInstance.class}); if (loadBalancer == null) { throw new NotFoundException("No loadbalancer available for " + uri.getHost()); } else { return loadBalancer.choose(this.createRequest()); } }//选择服务实例 private Request createRequest() { return ReactiveLoadBalancer.REQUEST; }}ReactorLoadBalancer：负载均衡接口
public interface ReactorLoadBalancer<T> extends ReactiveLoadBalancer<T> { Mono<Response<T>> choose(Request request); default Mono<Response<T>> choose() { return this.choose(REQUEST); }} *********************** public interface ReactorServiceInstanceLoadBalancer extends ReactorLoadBalancer<ServiceInstance> {}RoundRobinLoadbalancer：负载均衡使用轮询
public class RoundRobinLoadBalancer implements ReactorServiceInstanceLoadBalancer { private static final Log log = LogFactory.getLog(RoundRobinLoadBalancer.class); private final AtomicInteger position; private ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider; private final String serviceId; ************构造方法 public RoundRobinLoadBalancer(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider, String serviceId) { public RoundRobinLoadBalancer(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider, String serviceId, int seedPosition) { ************普通方法 public Mono<Response<ServiceInstance>> choose(Request request) { if (this.serviceInstanceListSupplierProvider != null) { ServiceInstanceListSupplier supplier = (ServiceInstanceListSupplier)this.serviceInstanceListSupplierProvider.getIfAvailable(NoopServiceInstanceListSupplier::new); return ((Flux)supplier.get()).next().map(this::getInstanceResponse); } else { ServiceInstanceSupplier supplier = (ServiceInstanceSupplier)this.serviceInstanceSupplier.getIfAvailable(NoopServiceInstanceSupplier::new); return ((Flux)supplier.get()).collectList().map(this::getInstanceResponse); } } private Response<ServiceInstance> getInstanceResponse(List<ServiceInstance> instances) { if (instances.isEmpty()) { log.warn("No servers available for service: " + this.serviceId); return new EmptyResponse(); } else { int pos = Math.abs(this.position.incrementAndGet()); ServiceInstance instance = (ServiceInstance)instances.get(pos % instances.size()); return new DefaultResponse(instance); } }//使用轮询获取实例}示例：
参数id为偶数时，输出hello new version
网关
配置文件
spring: application: name: hello-gateway cloud: consul: host: 172.18.0.20 port: 8500 loadbalancer: ribbon: enabled: false gateway: routes: - id: myRoute uri: lb://hello-service predicates: - Path=/hello自定义过滤器
@Componentpublic class CustomLoadBalancerClientFilter implements GlobalFilter, Ordered { private static final Log log = LogFactory.getLog(org.springframework.cloud.gateway.filter.ReactiveLoadBalancerClientFilter.class); @Resource private final LoadBalancerClientFactory clientFactory; @Resource private LoadBalancerProperties properties; public CustomLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties properties) { this.clientFactory = clientFactory; this.properties = properties; } public int getOrder() { return 10149; } public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { URI url = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR); String schemePrefix = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR); if (url != null && ("lb".equals(url.getScheme()) || "lb".equals(schemePrefix))) { ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url); if (log.isTraceEnabled()) { log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() + " url before: " + url); } return this.choose(exchange).doOnNext((response) -> { if (!response.hasServer()) { throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost()); } else { URI uri = exchange.getRequest().getURI(); String overrideScheme = null; if (schemePrefix != null) { overrideScheme = url.getScheme(); } int id=Integer.parseInt(Objects.requireNonNull(exchange.getRequest().getQueryParams().getFirst("id"))); if (id%2==0){ while (!"new".equals(response.getServer().getMetadata().get("version"))){ try { response=this.choose(exchange).toFuture().get(); }catch (Exception e){ System.out.println(e.getMessage()); } } } DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance(response.getServer(), overrideScheme); System.out.println(exchange.getRequest().getQueryParams().getFirst("id")+"对应server的version为："+serviceInstance.getMetadata().get("version")); URI requestUrl = LoadBalancerUriTools.reconstructURI(serviceInstance, uri); if (log.isTraceEnabled()) { log.trace("LoadBalancerClientFilter url chosen: " + requestUrl); } exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl); } }).then(chain.filter(exchange)); } else { return chain.filter(exchange); } } private Mono<Response<ServiceInstance>> choose(ServerWebExchange exchange) { URI uri = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR); assert uri != null; ReactorLoadBalancer<ServiceInstance> loadBalancer = this.clientFactory.getInstance(uri.getHost(), ReactorLoadBalancer.class, new Class[]{ServiceInstance.class}); if (loadBalancer == null) { throw new NotFoundException("No loadbalancer available for " + uri.getHost()); } else { return loadBalancer.choose(this.createRequest()); } } private Request createRequest() { return ReactiveLoadBalancer.REQUEST; }}同名应用hello-service1
配置文件
spring: application: name: hello-service cloud: consul: host: 172.18.0.20 port: 8500 discovery: instance-id: ${spring.application.name}-${random.int} tags: version=oldcontroller 层
@RestControllerpublic class HelloController { @RequestMapping("/hello") public String hello(){ return "hello old version"; }}同名应用hello-service2
配置文件
spring: application: name: hello-service cloud: consul: host: 172.18.0.20 port: 8500 discovery: instance-id: ${spring.application.name}-${random.int} tags: version=newcontroller 层
@RestControllerpublic class HelloController { @RequestMapping("/hello") public String hello(){ return "hello new version"; }}测试输出
consul注册的应用
参数测试
当id为偶数时，输出为hello new version
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