摘要：先看看是怎么獲取我們配置的路由在啟動時，幫我們注冊了一系列這里注入所有，我們在配置文件里配置的路由就是通過子類來完成的，可以參考實現(xiàn)自己的的存儲，會在后面轉換成接著看類里的獲取路由定義方法即輪訓所有的市現(xiàn)率調用，這樣就把所有整合到一起了接著

先看看gateway是怎么獲取我們配置的路由：
在gateway啟動時，GatewayAutoConfiguration幫我們注冊了一系列beans

    @Bean
    @Primary
    public RouteDefinitionLocator routeDefinitionLocator(List routeDefinitionLocators) {
        //這里注入所有RouteDefinitionLocator，我們在配置文件里配置的路由就是通過子類PropertiesRouteDefinitionLocator來完成的，
        //可以參考InMemoryRouteDefinitionRepository實現(xiàn)自己的RouteDefinition的存儲，RouteDefinition會在后面轉換成Route
        return new CompositeRouteDefinitionLocator(Flux.fromIterable(routeDefinitionLocators));
    }

    //接著看CompositeRouteDefinitionLocator類里的獲取路由定義方法：
    public Flux getRouteDefinitions() {
        //即輪訓所有RouteDefinitionLocator的市現(xiàn)率調用getRouteDefinitions，這樣就把所有RouteDefinition整合到一起了
        return this.delegates.flatMap(RouteDefinitionLocator::getRouteDefinitions);
    }
    
    //接著看GatewayAutoConfiguration，剛才的bean RouteDefinitionLocator 作為參數(shù)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類：
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后綴，所以配置時就可以寫成
        //predicates:
        //    - Path=/abc/*
        //的形式而不用寫完整的PathRoutePredicateFactory    
        initFactories(predicates);
        //把bean名字里的GatewayFilterFactory去掉，所以我們配置文件里配置時也要把GatewayFilterFactory去掉，不然會找不到
        gatewayFilterFactories.forEach(factory -> this.gatewayFilterFactories.put(factory.name(), factory));
        this.gatewayProperties = gatewayProperties;
    }
    ······ 

    @Override
    public Flux getRoutes() {
        return this.routeDefinitionLocator.getRouteDefinitions()
                .map(this::convertToRoute)//獲取所有的RouteDefinition后轉為Route
                //TODO: error handling
                .map(route -> {
                    if (logger.isDebugEnabled()) {
                        logger.debug("RouteDefinition matched: " + route.getId());
                    }
                    return route;
                });
 
    }

    private Route convertToRoute(RouteDefinition routeDefinition) {
        //獲取所有匹配規(guī)則，所有的規(guī)則都滿足才走對應Route
        AsyncPredicate predicate = combinePredicates(routeDefinition);
        //獲取全部過濾器
        List gatewayFilters = getFilters(routeDefinition);

        return Route.async(routeDefinition)
                .asyncPredicate(predicate)
                .replaceFilters(gatewayFilters)
                .build();
    }
 

    private List getFilters(RouteDefinition routeDefinition) {
        List filters = new ArrayList<>();

        //把全局過濾器添加到當前路由，loadGatewayFilters調用GatewayFilterFactory里的apply配置類里面的靜態(tài)Config類，并且把沒實現(xiàn)Ordered接口的類用OrderedGatewayFilter代理一下，方便下面排序
        if (!this.gatewayProperties.getDefaultFilters().isEmpty()) {
            filters.addAll(loadGatewayFilters("defaultFilters",
                    this.gatewayProperties.getDefaultFilters()));
        }
        //添加本條路由定義的過濾器
        if (!routeDefinition.getFilters().isEmpty()) {
            filters.addAll(loadGatewayFilters(routeDefinition.getId(), routeDefinition.getFilters()));
        }
        //排序
        AnnotationAwareOrderComparator.sort(filters);
        return filters;
    }

    private AsyncPredicate combinePredicates(RouteDefinition routeDefinition) { 
        //獲取路由的判斷條件，比如我們大多是根據(jù)url判斷，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);//如果有多個匹配規(guī)則就要滿足所有的才可以
        }
        //返回的結果會在RoutePredicateHandlerMapping類里使用apply方法調用 
        return predicate;
    }

    @SuppressWarnings("unchecked")
    private AsyncPredicate lookup(RouteDefinition route, PredicateDefinition predicate) {
        RoutePredicateFactory