SpringCloud Gateway 路由转发性能优化_routepredicatehandlermapping调优

对源码做简单修改，比如，Path 匹配 /mock/** 则对路由查找结果进行缓存（注意这里缓存策略和方式仅仅是举例，根据实际需求情况来做）

public static final String MOCK_PATCH = "/mock/**";private Map<String, Route> hashCache = new ConcurrentHashMap<>(1024);​protected Mono<Route> lookupRoute(ServerWebExchange exchange) {
    String path = exchange.getRequest().getPath().subPath(0).value();  //符合Path规则，优先从缓存Map获取，时间复杂度近似于O(1)  if (pathMatcher.match(MOCK_PATCH, path)) {
      return Mono.justOrEmpty(hashCache.get(path))               .switchIfEmpty(getRouteMono(exchange, path));  }  return getRouteMono(exchange, path);}​private Mono<Route> getRouteMono(ServerWebExchange exchange, String path) {
    return this.routeLocator.getRoutes()      //... 略过      .map(route -> {
          if (logger.isDebugEnabled()) {
            logger.debug("Route matched: " + route.getId());        }        validateRoute(route, exchange);        //符合Path规则，缓存路由        if (pathMatcher.match(MOCK_PATCH, path)) {
            hashCache.put(path, route);        }        return route;      });}

继续查阅源码，找到RoutePredicateHandlerMapping 是如何装配的。在GatewayAutoConfiguration 中实现了 SpringCloud Gateway 内部组件的自动装配，RoutePredicateHandlerMapping 也在其中，代码入下：

@Beanpublic RoutePredicateHandlerMapping routePredicateHandlerMapping(FilteringWebHandler webHandler,    RouteLocator routeLocator, GlobalCorsProperties globalCorsProperties, Environment environment) {
    return new RoutePredicateHandlerMapping(webHandler, routeLocator, globalCorsProperties, environment);}

很遗憾，官方没有给这个自动装配添加条件，我们无法自行装配替代默认装配。

我们只能采取以下步骤：

1. 在 Springboot 启动类上增加排除 GatewayAutoConfiguration 的自动装配配置；

2. 继承 GatewayAutoConfiguration 并完全拷贝其装配条件；

3. 覆盖父类 routePredicateHandlerMapping方法，给装配添加条件；

4. 继承RoutePredicateHandlerMapping ，覆盖其 lookupRoute方法，符合一定条件的请求，优先从缓存中查找路由。

改造 Gateway

修改启动类，排除自动装配

@SpringBootApplication(exclude = GatewayConfiguration.class)public class GatewayApplication {
    public static void main(String[] args) {
      SpringApplication.run(GatewayApplication.class, args);  }}

继承 GatewayAutoConfiguration

@Configuration(proxyBeanMethods = false)@ConditionalOnProperty(name = "spring.cloud.gateway.enabled", matchIfMissing = true)@EnableConfigurationProperties@AutoConfigureBefore({HttpHa