1.說明
本文詳細介紹Spring Cloud建立Gateway子產品的方法，
基于已經建立好的Spring Cloud父工程，
請參考SpringCloud建立項目父工程,
和已經建立好的Eureka子工程，
請參考SpringCloud建立Eureka子產品,
建立Gateway子產品這個子工程，
作為Spring Cloud的網關路由。
2.建立gateway子產品
這一步建立一個Maven Module，
作為Spring Cloud的父工程下的一個子工程：
在父工程spring-cloud-demo上右鍵 -> New -> Other... -> Maven -> Maven Project
勾選Create a simple project(skip archetype selection),
輸入Module Name:gateway,
檢視Parent Project:spring-cloud-demo，
如果不是自己選擇的父工程，請重新選擇。
點選Finish完成工程建立。
3.添加依賴
在pom.xml中增加eureka-client的依賴,
以及spring-cloud-starter-gateway的依賴：
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
</dependencies> 4.新增配置檔案
在src/main/resource目錄下新增application.yml檔案，
并且增加如下配置：
server:
port: 6001
spring:
application:
name: gateway
cloud:
gateway:
routes:
#路由的ID，沒有固定規則但要求唯一，建議配合服務名
- id: payment_routh
#比對後提供服務的路由位址
uri: http://news.baidu.com
predicates:
#斷言,路徑相比對的進行路由
- Path= /guonei/**
eureka:
instance:
#eureka用戶端的執行個體名字（主機名）
hostname: gateway-service
client:
service-url:
#表示向注冊中心注冊自己
register-with-eureka: true
#表示需要去注冊中心檢索服務
fetch-registry: true
#與eureka server互動的位址，包括查詢服務和注冊服務
defaultZone: http://localhost:7001/eureka 主要是用于連接配接Eureka服務中心，
以及配置的Gateway的路由配置。
5.新增主啟動類
在src/main/java目錄下新增主啟動類，
Package:com.yuwen.spring.gateway
Name:GatewayApplication
然後修改GatewayApplication.java如下,
注意一定要有EnableEurekaClient注解，
表示這是一個Eureka的用戶端：
package com.yuwen.spring.gateway;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@SpringBootApplication
@EnableEurekaClient
public class GatewayApplication {
public static void main(String[] args) {
SpringApplication.run(GatewayApplication.class, args);
}
} 6.啟動gateway
右鍵主啟動類GatewayApplication.java，
Run As ... -> Java Application
主要提前啟動Eureka Server服務，
成功啟動日志如下，
可以看到對外提供的服務端口是6001：
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.3.1.RELEASE)
2020-07-10 12:24:23.363 INFO 18968 --- [ main] c.y.spring.gateway.GatewayApplication : No active profile set, falling back to default profiles: default
2020-07-10 12:24:23.780 INFO 18968 --- [ main] o.s.cloud.context.scope.GenericScope : BeanFactory id=db5a2a8d-f793-34a6-b94a-45993e42245a
2020-07-10 12:24:23.833 INFO 18968 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerBeanPostProcessorAutoConfiguration' of type [org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerBeanPostProcessorAutoConfiguration] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2020-07-10 12:24:23.834 INFO 18968 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerBeanPostProcessorAutoConfiguration$ReactiveLoadBalancerConfig' of type [org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerBeanPostProcessorAutoConfiguration$ReactiveLoadBalancerConfig] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2020-07-10 12:24:23.835 INFO 18968 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'deferringLoadBalancerExchangeFilterFunction' of type [org.springframework.cloud.client.loadbalancer.reactive.DeferringLoadBalancerExchangeFilterFunction] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2020-07-10 12:24:23.905 WARN 18968 --- [ main] c.n.c.sources.URLConfigurationSource : No URLs will be polled as dynamic configuration sources.
2020-07-10 12:24:23.905 INFO 18968 --- [ main] c.n.c.sources.URLConfigurationSource : To enable URLs as dynamic configuration sources, define System property archaius.configurationSource.additionalUrls or make config.properties available on classpath.
2020-07-10 12:24:23.908 WARN 18968 --- [ main] c.n.c.sources.URLConfigurationSource : No URLs will be polled as dynamic configuration sources.
2020-07-10 12:24:23.908 INFO 18968 --- [ main] c.n.c.sources.URLConfigurationSource : To enable URLs as dynamic configuration sources, define System property archaius.configurationSource.additionalUrls or make config.properties available on classpath.
2020-07-10 12:24:26.134 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [After]
2020-07-10 12:24:26.134 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Before]
2020-07-10 12:24:26.134 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Between]
2020-07-10 12:24:26.134 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Cookie]
2020-07-10 12:24:26.134 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Header]
2020-07-10 12:24:26.134 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Host]
2020-07-10 12:24:26.134 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Method]
2020-07-10 12:24:26.135 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Path]
2020-07-10 12:24:26.135 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Query]
2020-07-10 12:24:26.135 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [ReadBodyPredicateFactory]
2020-07-10 12:24:26.135 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [RemoteAddr]
2020-07-10 12:24:26.135 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Weight]
2020-07-10 12:24:26.135 INFO 18968 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [CloudFoundryRouteService]
2020-07-10 12:24:27.507 WARN 18968 --- [ main] ockingLoadBalancerClientRibbonWarnLogger : You already have RibbonLoadBalancerClient on your classpath. It will be used by default. As Spring Cloud Ribbon is in maintenance mode. We recommend switching to BlockingLoadBalancerClient instead. In order to use it, set the value of `spring.cloud.loadbalancer.ribbon.enabled` to `false` or remove spring-cloud-starter-netflix-ribbon from your project.
2020-07-10 12:24:27.513 WARN 18968 --- [ main] eactorLoadBalancerClientRibbonWarnLogger : You have RibbonLoadBalancerClient on your classpath. LoadBalancerExchangeFilterFunction that uses it under the hood will be used by default. Spring Cloud Ribbon is now in maintenance mode, so we suggest switching to ReactorLoadBalancerExchangeFilterFunction instead. In order to use it, set the value of `spring.cloud.loadbalancer.ribbon.enabled` to `false` or remove spring-cloud-starter-netflix-ribbon from your project.
2020-07-10 12:24:27.564 INFO 18968 --- [ main] o.s.c.n.eureka.InstanceInfoFactory : Setting initial instance status as: STARTING
2020-07-10 12:24:27.657 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Initializing Eureka in region us-east-1
2020-07-10 12:24:28.214 INFO 18968 --- [ main] c.n.d.provider.DiscoveryJerseyProvider : Using JSON encoding codec LegacyJacksonJson
2020-07-10 12:24:28.214 INFO 18968 --- [ main] c.n.d.provider.DiscoveryJerseyProvider : Using JSON decoding codec LegacyJacksonJson
2020-07-10 12:24:28.286 INFO 18968 --- [ main] c.n.d.provider.DiscoveryJerseyProvider : Using XML encoding codec XStreamXml
2020-07-10 12:24:28.286 INFO 18968 --- [ main] c.n.d.provider.DiscoveryJerseyProvider : Using XML decoding codec XStreamXml
2020-07-10 12:24:28.392 INFO 18968 --- [ main] c.n.d.s.r.aws.ConfigClusterResolver : Resolving eureka endpoints via configuration
2020-07-10 12:24:28.815 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Disable delta property : false
2020-07-10 12:24:28.815 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Single vip registry refresh property : null
2020-07-10 12:24:28.815 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Force full registry fetch : false
2020-07-10 12:24:28.815 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Application is null : false
2020-07-10 12:24:28.815 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Registered Applications size is zero : true
2020-07-10 12:24:28.815 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Application version is -1: true
2020-07-10 12:24:28.815 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Getting all instance registry info from the eureka server
2020-07-10 12:24:28.943 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : The response status is 200
2020-07-10 12:24:28.944 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Starting heartbeat executor: renew interval is: 30
2020-07-10 12:24:28.945 INFO 18968 --- [ main] c.n.discovery.InstanceInfoReplicator : InstanceInfoReplicator onDemand update allowed rate per min is 4
2020-07-10 12:24:28.948 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Discovery Client initialized at timestamp 1594355068947 with initial instances count: 0
2020-07-10 12:24:28.948 INFO 18968 --- [ main] o.s.c.n.e.s.EurekaServiceRegistry : Registering application GATEWAY with eureka with status UP
2020-07-10 12:24:28.949 INFO 18968 --- [ main] com.netflix.discovery.DiscoveryClient : Saw local status change event StatusChangeEvent [timestamp=1594355068949, current=UP, previous=STARTING]
2020-07-10 12:24:28.950 INFO 18968 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient : DiscoveryClient_GATEWAY/yuwen-asiainfo:gateway:6001: registering service...
2020-07-10 12:24:29.004 INFO 18968 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient : DiscoveryClient_GATEWAY/yuwen-asiainfo:gateway:6001 - registration status: 204
2020-07-10 12:24:29.505 INFO 18968 --- [ main] o.s.b.web.embedded.netty.NettyWebServer : Netty started on port(s): 6001
2020-07-10 12:24:29.506 INFO 18968 --- [ main] .s.c.n.e.s.EurekaAutoServiceRegistration : Updating port to 6001
2020-07-10 12:24:30.752 INFO 18968 --- [ main] c.y.spring.gateway.GatewayApplication : Started GatewayApplication in 9.197 seconds (JVM running for 10.148)
2020-07-10 12:24:58.947 INFO 18968 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient : Disable delta property : false
2020-07-10 12:24:58.947 INFO 18968 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient : Single vip registry refresh property : null
2020-07-10 12:24:58.947 INFO 18968 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient : Force full registry fetch : false
2020-07-10 12:24:58.947 INFO 18968 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient : Application is null : false
2020-07-10 12:24:58.947 INFO 18968 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient : Registered Applications size is zero : true
2020-07-10 12:24:58.947 INFO 18968 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient : Application version is -1: false
2020-07-10 12:24:58.947 INFO 18968 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient : Getting all instance registry info from the eureka server
2020-07-10 12:24:58.972 INFO 18968 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient : The response status is 200 7.測試效果
檢視上面gateway的路由配置，
會把http://localhost:6001/guonei
的通路自動轉到http://news.baidu.com/guonei，
即通過gateway請求到百度新聞國内頁面。
浏覽器通路效果如下：
