環(huán)境：springcloud Hoxton.SR11

(資料圖片)

本節(jié)主要了解系統(tǒng)中的謂詞與配置的路由信息是如何進行初始化關聯(lián)生成路由對象的。每個謂詞工廠中的Config對象又是如何被解析配置的。

所有的謂詞工廠中的Config中屬性值是如何被配置的。

在SpringCloud Gateway中的所有謂詞工廠如下：

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命名規(guī)則：XxxRoutePredicateFactory。所有的這些謂詞工廠都是如下的繼承關系

public class MethodRoutePredicateFactory extends   AbstractRoutePredicateFactory// public class PathRoutePredicateFactory extends AbstractRoutePredicateFactory// ...

所有的謂詞工廠繼承的AbstractRoutePredicateFactory中的泛型都是內(nèi)部類的Config。這個是如何被配置上值的呢？

在下面這個類中配置了所有的Predicate和Filter。

public class GatewayAutoConfiguration {  @Bean  @ConditionalOnEnabledPredicate  public PathRoutePredicateFactory pathRoutePredicateFactory() {    return new PathRoutePredicateFactory();  }  @Bean  @ConditionalOnEnabledPredicate  public QueryRoutePredicateFactory queryRoutePredicateFactory() {    return new QueryRoutePredicateFactory();  }  @Bean  public RouteLocator routeDefinitionRouteLocator(GatewayProperties properties, List gatewayFilters, List predicates, RouteDefinitionLocator routeDefinitionLocator, ConfigurationService configurationService) {    return new RouteDefinitionRouteLocator(routeDefinitionLocator, predicates,            gatewayFilters, properties, configurationService);  }  @Bean  @Primary  @ConditionalOnMissingBean(name = "cachedCompositeRouteLocator")  public RouteLocator cachedCompositeRouteLocator(List routeLocators) {    return new CachingRouteLocator(new CompositeRouteLocator(Flux.fromIterable(routeLocators)));  }}

這里會層層委托最終查找查找路由定位會交給RouteDefinitionRouteLocator。CachingRouteLocator起到緩存的作用，將配置的所有路由信息保存。

注意：這里的路由信息是在容器啟動后就會被初始化的。

public class CachingRouteLocator {  private final RouteLocator delegate;  private final Flux routes;  private final Map cache = new ConcurrentHashMap<>();  private ApplicationEventPublisher applicationEventPublisher;  public CachingRouteLocator(RouteLocator delegate) {    this.delegate = delegate;    routes = CacheFlux.lookup(cache, CACHE_KEY, Route.class) .onCacheMissResume(this::fetch);  }  private Flux fetch() {    return this.delegate.getRoutes().sort(AnnotationAwareOrderComparator.INSTANCE);  }}

實例化CachingRouteLocator就開始查找所有配置的Route信息。最終的會委托給RouteDefinitionRouteLocator

RouteDefinitionRouteLocator構造函數(shù)中的initFactories方法用來映射路由工廠的XxxRoutePredicateFactory。

private void initFactories(List predicates) {  predicates.forEach(factory -> {    String key = factory.name();    if (this.predicates.containsKey(key)) {      this.logger.warn("A RoutePredicateFactory named " + key + " already exists, class: " + this.predicates.get(key) + ". It will be overwritten.");    }    this.predicates.put(key, factory);  });}

方法中解析每一個謂詞工廠對應的名稱然后緩存到predicates 集合中。

factory.name()方法解析謂詞名稱。

default String name() {  return NameUtils.normalizeRoutePredicateName(getClass());}

CachingRouteLocator是個緩存路由定位器，是個首選的RouteLocator（@Primary）,這里將RouteDefinitionRouteLocator進行了合并。

getRoutes---》convertToRoute---》combinePredicates---》lookup。

根據(jù)上面的自動配置也知道了在服務啟動時就進行初始化所有路由信息了。

獲取路由信息

public Flux getRoutes() {  Flux routes = this.routeDefinitionLocator.getRouteDefinitions() .map(this::convertToRoute);  routes = routes.onErrorContinue((error, obj) -> {    return routes.map(route -> {            return route;  });}

合并謂詞(鏈式調(diào)用)

private AsyncPredicate combinePredicates(            RouteDefinition routeDefinition) {  // other code  for (PredicateDefinition andPredicate : predicates.subList(1, predicates.size())) {    AsyncPredicate found = lookup(routeDefinition, andPredicate);    predicate = predicate.and(found);  }  return predicate;}

進入lookup中

private AsyncPredicate lookup(RouteDefinition route, PredicateDefinition predicate) {  RoutePredicateFactory