先看看gateway是怎么获取我们配置的路由：
在gateway启动时，GatewayAutoConfiguration帮我们注册了一系列beans
@Bean @Primary public RouteDefinitionLocator routeDefinitionLocator(List routeDefinitionLocators) { //这里注入所有RouteDefinitionLocator，我们在配置文件里配置的路由就是通过子类PropertiesRouteDefinitionLocator来完成的， //可以参考InMemoryRouteDefinitionRepository实现自己的RouteDefinition的存储，RouteDefinition会在后面转换成Route return new CompositeRouteDefinitionLocator(Flux.fromIterable(routeDefinitionLocators)); } //接着看CompositeRouteDefinitionLocator类里的获取路由定义方法： public Flux getRouteDefinitions() { //即轮训所有RouteDefinitionLocator的市现率调用getRouteDefinitions，这样就把所有RouteDefinition整合到一起了 return this.delegates.flatMap(RouteDefinitionLocator::getRouteDefinitions); } //接着看GatewayAutoConfiguration，刚才的bean RouteDefinitionLocator 作为参数注入到routeDefinitionLocator @Bean public RouteLocator routeDefinitionRouteLocator(GatewayProperties properties, List GatewayFilters, List predicates, RouteDefinitionLocator routeDefinitionLocator) { return new RouteDefinitionRouteLocator(routeDefinitionLocator, predicates, GatewayFilters, properties); } //看RouteDefinitionRouteLocator类：public class RouteDefinitionRouteLocator implements RouteLocator, BeanFactoryAware, ApplicationEventPublisherAware { ······ public RouteDefinitionRouteLocator(RouteDefinitionLocator routeDefinitionLocator, List predicates, List gatewayFilterFactories, GatewayProperties gatewayProperties) { this.routeDefinitionLocator = routeDefinitionLocator; //RoutePredicateFactory放到map里,去掉RoutePredicateFactory后缀，所以配置时就可以写成 //predicates: // - Path=/abc/* //的形式而不用写完整的PathRoutePredicateFactory initFactories(predicates); //把bean名字里的GatewayFilterFactory去掉，所以我们配置文件里配置时也要把GatewayFilterFactory去掉，不然会找不到 gatewayFilterFactories.forEach(factory -> this.gatewayFilterFactories.put(factory.name(), factory)); this.gatewayProperties = gatewayProperties; } ······ @Override public Flux getRoutes() { return this.routeDefinitionLocator.getRouteDefinitions() .map(this::convertToRoute)//获取所有的RouteDefinition后转为Route //TODO: error handling .map(route -> { if (logger.isDebugEnabled()) { logger.debug("RouteDefinition matched: " + route.getId()); } return route; }); } private Route convertToRoute(RouteDefinition routeDefinition) { //获取所有匹配规则，所有的规则都满足才走对应Route AsyncPredicate predicate = combinePredicates(routeDefinition); //获取全部过滤器 List gatewayFilters = getFilters(routeDefinition); return Route.async(routeDefinition) .asyncPredicate(predicate) .replaceFilters(gatewayFilters) .build(); } private List getFilters(RouteDefinition routeDefinition) { List filters = new ArrayList<>(); //把全局过滤器添加到当前路由，loadGatewayFilters调用GatewayFilterFactory里的apply配置类里面的静态Config类，并且把没实现Ordered接口的类用OrderedGatewayFilter代理一下，方便下面排序 if (!this.gatewayProperties.getDefaultFilters().isEmpty()) { filters.addAll(loadGatewayFilters("defaultFilters", this.gatewayProperties.getDefaultFilters())); } //添加本条路由定义的过滤器 if (!routeDefinition.getFilters().isEmpty()) { filters.addAll(loadGatewayFilters(routeDefinition.getId(), routeDefinition.getFilters())); } //排序 AnnotationAwareOrderComparator.sort(filters); return filters; } private AsyncPredicate combinePredicates(RouteDefinition routeDefinition) { //获取路由的判断条件，比如我们大多是根据url判断，用的是PathRoutePredicateFactory List predicates = routeDefinition.getPredicates(); AsyncPredicate predicate = lookup(routeDefinition, predicates.get(0)); for (PredicateDefinition andPredicate : predicates.subList(1, predicates.size())) { AsyncPredicate found = lookup(routeDefinition, andPredicate); predicate = predicate.and(found);//如果有多个匹配规则就要满足所有的才可以 } //返回的结果会在RoutePredicateHandlerMapping类里使用apply方法调用 return predicate; } @SuppressWarnings("unchecked") private AsyncPredicate lookup(RouteDefinition route, PredicateDefinition predicate) { RoutePredicateFactory
说了那么多终于把网关匹配路由的流程说完了，如果上面都看明白的话，动态路由就好办了
网关已经把InMemoryRouteDefinitionRepository注册成bean（也可以参考这个类自己实现RouteDefinitionRepository接口），我们把它当作个service注入到controller,
前端把RouteDefinition用json的格式post过来，我们调用InMemoryRouteDefinitionRepository的save或者delete方法，再用spring的事件触发RefreshRoutesEvent事件来刷新路由就行了，等下次请求的时候就可以拿到新的路由配置了
顺序是：
1.RoutePredicateHandlerMapping 的lookupRoute方法，由于路由刷新事件把路由缓存清了，所以重新获取
2.CompositeRouteLocator 的getRoutes方法遍历所有RouteLocator实现类的getRoutes方法
3.RouteDefinitionRouteLocator 的getRoutes方法里重新获取了所有的路由定义，也就把我们刚刚用事件添加的路由也获取了