关于java:Zuul-路由加载

Zuul- 启动，咱们提到了 zuulRefreshRoutesListener，能够用来动静刷新路由，咱们看看他是怎么加载的。
一下这几个事件会触发 reset 办法。

public void onApplicationEvent(ApplicationEvent event) {
    if (event instanceof ContextRefreshedEvent
            || event instanceof RefreshScopeRefreshedEvent
            || event instanceof RoutesRefreshedEvent
            || event instanceof InstanceRegisteredEvent) {reset();
    }
    else if (event instanceof ParentHeartbeatEvent) {ParentHeartbeatEvent e = (ParentHeartbeatEvent) event;
        resetIfNeeded(e.getValue());
    }
    else if (event instanceof HeartbeatEvent) {HeartbeatEvent e = (HeartbeatEvent) event;
        resetIfNeeded(e.getValue());
    }
}

DiscoveryClientRouteLocator#locateRoutes

追着这个办法上来，咱们最初会到 DiscoveryClientRouteLocator#locateRoutes 办法。这里次要是获取两个中央的配置，一个是咱们的配置文件，一个是 Eureka 的注册表信息。

protected LinkedHashMap<String, ZuulRoute> locateRoutes() {LinkedHashMap<String, ZuulRoute> routesMap = new LinkedHashMap<>();
    // 先调用父类的办法，routesMap.putAll(super.locateRoutes());
    if (this.discovery != null) {Map<String, ZuulRoute> staticServices = new LinkedHashMap<>();
        for (ZuulRoute route : routesMap.values()) {String serviceId = route.getServiceId();
            if (serviceId == null) {serviceId = route.getId();
            }
            if (serviceId != null) {staticServices.put(serviceId, route);
            }
        }
        // 从 Eureka 获取注册表信息
        List<String> services = this.discovery.getServices();
        // 是否有过滤的条件
        String[] ignored = this.properties.getIgnoredServices()
                .toArray(new String[0]);
        for (String serviceId : services) {String key = "/" + mapRouteToService(serviceId) + "/**";
            if (staticServices.containsKey(serviceId)
                    && staticServices.get(serviceId).getUrl() == null) {ZuulRoute staticRoute = staticServices.get(serviceId);
                if (!StringUtils.hasText(staticRoute.getLocation())) {staticRoute.setLocation(serviceId);
                }
            }
            if (!PatternMatchUtils.simpleMatch(ignored, serviceId)
                    && !routesMap.containsKey(key)) {routesMap.put(key, new ZuulRoute(key, serviceId));
            }
        }
    }
    if (routesMap.get(DEFAULT_ROUTE) != null) {ZuulRoute defaultRoute = routesMap.get(DEFAULT_ROUTE);
        routesMap.remove(DEFAULT_ROUTE);
        routesMap.put(DEFAULT_ROUTE, defaultRoute);
    }
    // 返回本地配置 +Eureka 未过滤的注册表
    LinkedHashMap<String, ZuulRoute> values = new LinkedHashMap<>();
    for (Entry<String, ZuulRoute> entry : routesMap.entrySet()) {String path = entry.getKey();
        // Prepend with slash if not already present.
        if (!path.startsWith("/")) {path = "/" + path;}
        if (StringUtils.hasText(this.properties.getPrefix())) {path = this.properties.getPrefix() + path;
            if (!path.startsWith("/")) {path = "/" + path;}
        }
        values.put(path, entry.getValue());
    }
    return values;
}

Eureka 的注册表有个 IgnoredServices 配置，咱们能够对他进行过滤，这样防止服务名称间接裸露进去。

 zuul:
  ignoredServices: '*'
  routes:
    users: /myusers/**

SimpleRouteLocator#locateRoutes

读取本地的时候，间接从 ZuulProperties 取值。

protected Map<String, ZuulRoute> locateRoutes() {LinkedHashMap<String, ZuulRoute> routesMap = new LinkedHashMap<>();
    for (ZuulRoute route : this.properties.getRoutes().values()) {routesMap.put(route.getPath(), route);
    }
    return routesMap;
}

ZuulProperties 被加载的时候，因为有一个 @PostConstruct 注解，他会调用 init 办法。在这里会依据咱们的配置信息进行赋值 serviceId、id、path。

@PostConstruct
public void init() {for (Entry<String, ZuulRoute> entry : this.routes.entrySet()) {ZuulRoute value = entry.getValue();
        if (!StringUtils.hasText(value.getLocation())) {value.serviceId = entry.getKey();
        }
        if (!StringUtils.hasText(value.getId())) {value.id = entry.getKey();
        }
        if (!StringUtils.hasText(value.getPath())) {value.path = "/" + entry.getKey() + "/**";
        }
    }
}

流程图

动静路由

咱们晓得了什么时候触发路由的从新加载，那咱们能够在路由信息扭转的时候，就调用触发他的条件，比方 RoutesRefreshedEvent。
咱们晓得了他的加载流程，先本地再注册核心，咱们也能够自定义本人的加载流程，比方先本地，再数据库，数据库变更，就触发 RoutesRefreshedEvent 工夫，达到动静路由的目标。