Spring-Cloud-Gateway之RouteDefinition初始化加载

RouteDefinition路由定义，Spring-Cloud-Gateway通过RouteDefinition来转换生成具体的路由信息。RouteDefinition的信息是怎么加载初始化到网关系统中的，接下来阅读Spring-Cloud-Gateway的RouteDefinitionLocator（路由定义信息加载器）接口，学习RouteDefinition初始化加载

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首先查看RouteDefinitionLocator源码

/** * 路由定义信息的定位器， * 负责读取路由配置( org.springframework.cloud.gateway.route.RouteDefinition * 子类实现类 * 1.CachingRouteDefinitionLocator -RouteDefinitionLocator包装类， 缓存目标RouteDefinitionLocator 为routeDefinitions提供缓存功能 * 2.CompositeRouteDefinitionLocator -RouteDefinitionLocator包装类，组合多种 RouteDefinitionLocator 的实现，为 routeDefinitions提供统一入口 * 3.PropertiesRouteDefinitionLocator-从配置文件(GatewayProperties 例如，YML / Properties 等 ) 读取RouteDefinition * 4.DiscoveryClientRouteDefinitionLocator-从注册中心( 例如，Eureka / Consul / Zookeeper / Etcd 等 )读取RouteDefinition * 5.RouteDefinitionRepository-从存储器( 例如，内存 / Redis / MySQL 等 )读取RouteDefinition * @author Spencer Gibb */ public interface RouteDefinitionLocator { /** * 获取RouteDefinition * @return */ Flux<RouteDefinition> getRouteDefinitions(); } 

RouteDefinitionLocator接口有且仅有一个方法getRouteDefinitions，此方法获取RouteDefinition的核心方法，返回Flux<RouteDefinition>

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RouteDefinitionLocator 类图如下：

graph TD RouteDefinitionLocator-->CachingRouteDefinitionLocator RouteDefinitionLocator-->CompositeRouteDefinitionLocator RouteDefinitionLocator-->PropertiesRouteDefinitionLocator RouteDefinitionLocator-->DiscoveryClientRouteDefinitionLocator RouteDefinitionLocator-->RouteDefinitionRepository 

子类功能描述：

• CachingRouteDefinitionLocator：RouteDefinitionLocator包装类， 缓存目标RouteDefinitionLocator 为routeDefinitions提供缓存功能
• CompositeRouteDefinitionLocator -RouteDefinitionLocator包装类，组合多种 RouteDefinitionLocator 的实现，为 routeDefinitions提供统一入口
• PropertiesRouteDefinitionLocator-从配置文件(GatewayProperties 例如，YML / Properties 等 ) 读取RouteDefinition
• RouteDefinitionRepository-从存储器( 例如，内存 / Redis / MySQL 等 )读取RouteDefinition
• DiscoveryClientRouteDefinitionLocator-从注册中心( 例如，Eureka / Consul / Zookeeper / Etcd 等

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接下来详细看子类的源码分析主要实现功能

• PropertiesRouteDefinitionLocator

/** * 从Properties（GatewayProperties）中加载RouteDefinition信息 * @author Spencer Gibb */ public class PropertiesRouteDefinitionLocator implements RouteDefinitionLocator { /** * 从appliccation.yml中解析前缀为spring.cloud.gateway的配置 */ private final GatewayProperties properties; public PropertiesRouteDefinitionLocator(GatewayProperties properties) { this.properties = properties; } @Override public Flux<RouteDefinition> getRouteDefinitions() { return Flux.fromIterable(this.properties.getRoutes()); } } 

PropertiesRouteDefinitionLocator很简单从GatewayProperties实例获取RouteDefinition信息

• GatewayProperties 在GatewayProperties初始化加载文中已详细描述
• Flux 响应式编程

• CachingRouteDefinitionLocator

/** * RouteDefinitionLocator 包装实现类，实现了路由定义的本地缓存功能 * @author Spencer Gibb */ public class CachingRouteDefinitionLocator implements RouteDefinitionLocator { /** * 实际路由定义定位器 */ private final RouteDefinitionLocator delegate; private final Flux<RouteDefinition> routeDefinitions; /** * 路由定义的本地缓存 */ private final Map<String, List> cache = new HashMap<>(); public CachingRouteDefinitionLocator(RouteDefinitionLocator delegate) { this.delegate = delegate; routeDefinitions = CacheFlux.lookup(cache, "routeDefs", RouteDefinition.class) .onCacheMissResume(() -> this.delegate.getRouteDefinitions()); } } 

RouteDefinitionLocator包装类，缓存目标RouteDefinitionLocator 为routeDefinitions提供缓存功能

• DiscoveryClientRouteDefinitionLocator

public class DiscoveryClientRouteDefinitionLocator implements RouteDefinitionLocator { /** * 注册中心客户端 */ private final DiscoveryClient discoveryClient; /** * 本地配置信息 */ private final DiscoveryLocatorProperties properties; /** * 路由ID前缀 */ private final String routeIdPrefix; public DiscoveryClientRouteDefinitionLocator(DiscoveryClient discoveryClient, DiscoveryLocatorProperties properties) { this.discoveryClient = discoveryClient; this.properties = properties; if (StringUtils.hasText(properties.getRouteIdPrefix())) { this.routeIdPrefix = properties.getRouteIdPrefix(); } else { this.routeIdPrefix = this.discoveryClient.getClass().getSimpleName() + "_"; } } /** * 通过注册中心查找服务组装路由定义信息 * @return */ @Override public Flux<RouteDefinition> getRouteDefinitions() { ...代码在根据注册中心查找路由详细解析 } } 

DiscoveryClientRouteDefinitionLocator通过调用 DiscoveryClient 获取注册在注册中心的服务列表，生成对应的 RouteDefinition 数组

• CompositeRouteDefinitionLocator

/** * 组合多个 RouteDefinitionLocator 的实现，为 routeDefinitions提供统一入口 * @author Spencer Gibb */ public class CompositeRouteDefinitionLocator implements RouteDefinitionLocator { /** * 所有路由定义定位器实例集合 */ private final Flux<RouteDefinitionLocator> delegates; public CompositeRouteDefinitionLocator(Flux<RouteDefinitionLocator> delegates) { this.delegates = delegates; } @Override public Flux<RouteDefinition> getRouteDefinitions() { //将各个RouteDefinitionLocator的getRouteDefinitions合并返回统一的Flux<RouteDefinition> return this.delegates.flatMap(RouteDefinitionLocator::getRouteDefinitions); } } 

CompositeRouteDefinitionLocator 的主要作用就是将各个定位器合并提供统一的getRouteDefinitions方法入口

通过子类实现具体功能可以很清晰的看到定位器加载RouteDefinition整个流程

graph TD PropertiesRouteDefinitionLocator-->|配置文件加载初始化| CompositeRouteDefinitionLocator RouteDefinitionRepository-->|存储器中加载初始化| CompositeRouteDefinitionLocator DiscoveryClientRouteDefinitionLocator-->|注册中心加载初始化| CompositeRouteDefinitionLocator 

最终提供通过CompositeRouteDefinitionLocator提供统一的
getRouteDefinitions方法

RouteDefinitionLocator实例的初始化在GatewayAutoConfiguration中已经完成

GatewayDiscoveryClientAutoConfiguration

@Configuration @ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true) @AutoConfigureBefore(GatewayAutoConfiguration.class) @ConditionalOnClass({DispatcherHandler.class, DiscoveryClient.class}) @EnableConfigurationProperties public class GatewayDiscoveryClientAutoConfiguration { //初始化注册中心路由定义定位器 @Bean @ConditionalOnBean(DiscoveryClient.class) @ConditionalOnProperty(name = "spring.cloud.gateway.discovery.locator.enabled") public DiscoveryClientRouteDefinitionLocator discoveryClientRouteDefinitionLocator( DiscoveryClient discoveryClient, DiscoveryLocatorProperties properties) { return new DiscoveryClientRouteDefinitionLocator(discoveryClient, properties); } 

GatewayAutoConfiguration

   //初始化配置路由定义加载器 @Bean @ConditionalOnMissingBean public PropertiesRouteDefinitionLocator propertiesRouteDefinitionLocator(GatewayProperties properties) { return new PropertiesRouteDefinitionLocator(properties); } //初始化存储路由定义加载器 @Bean @ConditionalOnMissingBean(RouteDefinitionRepository.class) public InMemoryRouteDefinitionRepository inMemoryRouteDefinitionRepository() { return new InMemoryRouteDefinitionRepository(); } //初始化聚合路由定义加载器 @Bean @Primary public RouteDefinitionLocator routeDefinitionLocator(List<RouteDefinitionLocator> routeDefinitionLocators) { return new CompositeRouteDefinitionLocator(Flux.fromIterable(routeDefinitionLocators)); } 

在Spring-Cloud-Gateway初始化完成后需要的路由定义加载器已全部实例化完成，这样就为路由的加载创建完成了必要的条件。

 

作者：Mr_1214
链接：https://www.jianshu.com/p/b02c7495eb5e
来源：简书
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