本篇文章为大家展示了spring cloud 2.x中怎么实现Gateway路由网关，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。
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Spring Cloud Gateway是Spring Cloud的一个新项目，该项目是基于Spring5.0，Sprint Boot2.0和Project Reactor等技术开发的网关，它的目的是在微服务架构中提供一种简单有效的统一api路由管理方式。 Spring Cloud Gateway目标是要替代Netflix Zuul，其不仅提供统一的路由管理方式，还提供一套基于Fliter链的方式的网关其他功能，比如：限流、埋点、安全监控等。
Route(路由)：网关的基本模块，它有一个id、一个目标uri、一组断言和一组过滤器组成，如果断言为真，则路由匹配。
Predicate(断言)：是一个java8的Predicate。输入类型是一个ServerWebExchange。可以使用它来匹配来自HTTP请求的内容。
Filter(过滤器)：是org.springframework.cloud.gateway.filter.GatewayFilter的实例，可以使用它来修改请求和响应。
客户端向Spring Cloud Gateway发出请求。如果Gateway Handler映射确定请求与路由匹配，则将其发送到Gateway Web Handler。Gateway Web Handler通过特定于请求的筛选器链发送请求。筛选器由虚线分隔的原因是，筛选器可以在发送代理请求之前或之后执行逻辑。执行所有“pre”筛选逻辑，然后发出代理请求。在发出代理请求后，执行“POST”筛选逻辑。
org.springframework.boot spring-boot-starter-webflux org.springframework.cloud spring-cloud-starter-gateway org.springframework.cloud spring-cloud-starter-netflix-eureka-client
server: port: 8100 spring: application: name: spring-gateway cloud: gateway: discovery: locator: enabled: true eureka: instance: hostname: eureka1.server.com lease-renewal-interval-in-seconds: 5 lease-expiration-duration-in-seconds: 10 client: service-url: defaultZone: http://eureka1.server.com:8701/eureka/,http://eureka2.server.com:8702/eureka/,http://eureka3.server.com:8703/eureka/
Spring.cloud.gateway.discovery.locator.enabled:true 这里先简单使用了默认的创建路由规则,自动根据serviceid创建路由的功能
前几片文章中都在对应的启动类中增加了@EnableEurekaClient或@EnableDiscoveryClient注解，今天看文档突然发现，不用加@Enable*注解也可以自动添加到注册中心，是因为在Spring Cloud Edgware版本之后，只要加上相关的依赖，并进行相应的配置就可以将服务自动注册到服务发现组件上。
按顺序启动eureka-server、eureka-client、eureka-ribbon、spring-gateway服务。 打开浏览器，先去eureka-server服务中心看一下服务是否正常启动，如下如： 
截图中红框代表所有服务已经正常启动。 然后新打来浏览器输入：http://localhost:8100/SPRING-GATEWAY/EUREKA-RIBBON/sayHello，显示如下：
因为我们才用的是自动配置路由，所有这里url上的服务名称要全部大写，就是和服务注册中心保存一致。 这里我可以看一下spring-gate的启动日志，自动路由名称全部是大写。（个人觉得这里设计的不是很好）。
2019-10-12 16:40:35.870 INFO 97725 --- [ctor-http-nio-2] c.netflix.config.ChainedDynamicProperty : Flipping property: SPRING-GATEWAY.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-10-12 16:40:35.890 INFO 97725 --- [ctor-http-nio-2] c.n.u.concurrent.ShutdownEnabledTimer : Shutdown hook installed for: NFLoadBalancer-PingTimer-SPRING-GATEWAY
2019-10-12 16:40:35.890 INFO 97725 --- [ctor-http-nio-2] c.netflix.loadbalancer.BaseLoadBalancer : Client: SPRING-GATEWAY instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=SPRING-GATEWAY,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2019-10-12 16:40:35.895 INFO 97725 --- [ctor-http-nio-2] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater
2019-10-12 16:40:35.910 INFO 97725 --- [ctor-http-nio-2] c.netflix.config.ChainedDynamicProperty : Flipping property: SPRING-GATEWAY.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-10-12 16:40:35.911 INFO 97725 --- [ctor-http-nio-2] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client SPRING-GATEWAY initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=SPRING-GATEWAY,current list of Servers=[eureka1.server.com:8100],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:1; Active connections count: 0; Circuit breaker tripped count: 0; Active connections per server: 0.0;]
},Server stats: [[Server:eureka1.server.com:8100; Zone:defaultZone; Total Requests:0; Successive connection failure:0; Total blackout seconds:0; Last connection made:Thu Jan 01 08:00:00 CST 1970; First connection made: Thu Jan 01 08:00:00 CST 1970; Active Connections:0; total failure count in last (1000) msecs:0; average resp time:0.0; 90 percentile resp time:0.0; 95 percentile resp time:0.0; min resp time:0.0; max resp time:0.0; stddev resp time:0.0]
]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@3b80e99c
2019-10-12 16:40:36.008 INFO 97725 --- [tor-http-nio-10] c.netflix.config.ChainedDynamicProperty : Flipping property: EUREKA-RIBBON.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-10-12 16:40:36.009 INFO 97725 --- [tor-http-nio-10] c.n.u.concurrent.ShutdownEnabledTimer : Shutdown hook installed for: NFLoadBalancer-PingTimer-EUREKA-RIBBON
2019-10-12 16:40:36.010 INFO 97725 --- [tor-http-nio-10] c.netflix.loadbalancer.BaseLoadBalancer : Client: EUREKA-RIBBON instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=EUREKA-RIBBON,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2019-10-12 16:40:36.011 INFO 97725 --- [tor-http-nio-10] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater
2019-10-12 16:40:36.012 INFO 97725 --- [tor-http-nio-10] c.netflix.config.ChainedDynamicProperty : Flipping property: EUREKA-RIBBON.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-10-12 16:40:36.012 INFO 97725 --- [tor-http-nio-10] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client EUREKA-RIBBON initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=EUREKA-RIBBON,current list of Servers=[eureka1.server.com:8901],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:1; Active connections count: 0; Circuit breaker tripped count: 0; Active connections per server: 0.0;]
},Server stats: [[Server:eureka1.server.com:8901; Zone:defaultZone; Total Requests:0; Successive connection failure:0; Total blackout seconds:0; Last connection made:Thu Jan 01 08:00:00 CST 1970; First connection made: Thu Jan 01 08:00:00 CST 1970; Active Connections:0; total failure count in last (1000) msecs:0; average resp time:0.0; 90 percentile resp time:0.0; 95 percentile resp time:0.0; min resp time:0.0; max resp time:0.0; stddev resp time:0.0]
]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@19148ab同样的方式我可以请求eureka-feign，结果如下：
至此基于服务发现的默认路由规则就搭建完成。
server: port: 8100 spring: application: name: spring-gateway cloud: gateway: # discovery: # locator: # enabled: true # 开启通过服务中心的自动根据 serviceId 创建路由的功能 routes: - id: ribbon-route uri: lb://EUREKA-RIBBON order: 0 predicates: - Path=/ribbon/** filters: - StripPrefix=1 #去掉前缀，具体实现参考StripPrefixGatewayFilterFactory - AddResponseHeader=X-Response-Default-Foo, Default-Bar - id: feign-route uri: lb://EUREKA-FEIGN order: 0 predicates: - Path=/feign/** filters: - StripPrefix=1 - AddResponseHeader=X-Response-Default-Foo, Default-Bar eureka: instance: hostname: eureka1.server.com lease-renewal-interval-in-seconds: 5 lease-expiration-duration-in-seconds: 10 client: service-url: defaultZone: http://eureka1.server.com:8701/eureka/,http://eureka2.server.com:8702/eureka/,http://eureka3.server.com:8703/eureka/
StripPrefix: 接受一个非负整数，对应的具体实现是StripPrefixGatewayFilterFactory，做用是去掉前缀，整数对应层数。在本例中访问的/ribbon/sayHello，网关服务向后转发请求的时候会去掉/ribbon，eureka-ribbon收到的请求是：/sayHello。eureka-feign同理。
访问http://localhost:8100/ribbon/sayHello和http://localhost:8100/feign/feign/sayHello，如图下图显示：
ribbon:
feign:
Spring Cloud Gateway同时支持java的流式api的路由定义，可以和application.yml配合使用。
package spring.cloud.demo.spring.gateway.config;
import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class RoutesConfig {
@Bean
public RouteLocator routeLocator(RouteLocatorBuilder routeLocatorBuilder){
return routeLocatorBuilder.routes().route(r -> r.path("/ribbon/**")
.filters(f -> f.stripPrefix(1)
.addRequestHeader("X-Response-Default-Foo", "Default-Bar"))
.uri("lb://EUREKA-RIBBON")
.order(0)
.id("ribbon-route")
).build();
}
}上述内容就是spring cloud 2.x中怎么实现Gateway路由网关，你们学到知识或技能了吗？如果还想学到更多技能或者丰富自己的知识储备，欢迎关注创新互联行业资讯频道。
