Spring Cloud 新一代网关：Spring Cloud GateWay
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2022-07-14 23:18:23
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简介
简单点说：Spring Cloud GateWay就像医院里分诊台，将你引导到各个科室
Spring Cloud GateWay提供了一套简单有效的API路由管理方式，是基于Filter(过滤器)的方式提供网关的基本功能
作用：
- 安全验证
- 监控
- 限流
- 熔断
- 重试等
Netflix Zuul 由于Netflix公司迟迟不更新2.0，开发者已经对它失去信心了，反正我是失去了，Spring Cloud GateWay会一步一步的取代Zuul
为什么用网关？
服务网关 = 路由转发 + 过滤器
1、路由转发：接收一切外界请求，转发到后端的微服务上去；
2、过滤器：在服务网关中可以完成一系列的横切功能，例如权限校验、限流以及监控等，这些都可以通过过滤器完成（其实路由转发也是通过过滤器实现的）;
假设你开发一个电商服务，有会员，支付，商品等等服务
- 你会对每个服务都进行鉴权、限流、权限校验等逻辑？
- 每次上线一个服务都要申请域名，配置Nginx等等？
- 每个服务可能用不同的开发语言编写，那么可能会采用不同的协议，例如Dubbo,HTTP等，你也要适配这些协议？
- 商品服务业务量越来越大，需要拆分，那么需要客户端配合改造，这也是非常蛋疼的事情
这个时候网管服务就起作用了，类似Nginx的作用，将所有用户的请求转发给后端的服务器，但网关做的不仅仅只是简单的转发，也会针对流量做一些扩展，比如鉴权、限流、权限、熔断、协议转换、错误码统一、缓存、日志、监控、告警等，这样将通用的逻辑抽出来，由网关统一去做，业务方也能够更专注于业务逻辑，提升迭代的效率。
Spring Cloud GateWay的核心执行逻辑
核心逻辑 = 断言(Predicate:断言是否为true才允许转发) + 路由转发(Route) + 执行过滤链(Filter )
官网提供执行图：
执行流程：
-
① Gateway 接收客户端请求。
-
② 请求与 Predicate 进行匹配，获得到对应的 Route。匹配成功后，才能继续往下执行。
-
③ 请求经过 Filter 过滤器链，执行前置（prev）处理逻辑。
例如说，修改请求头信息等。
-
④ 请求被 Proxy Filter 转发至目标 URI，并最终获得响应。
一般来说，目标 URI 是被代理的微服务，如果是在 Spring Cloud 架构中。
-
⑤ 响应经过 Filter 过滤器链，执行后置（post）处理逻辑。
-
⑥ Gateway 返回响应给客户端。
其实，就类似就像SpringMVC 的 DispatcherServlet差不多，只是说 SpringMVC 最终转发到 JVM 进程内的指定方法，而 Gateway 最终转发到远程的目标 URI
下面是一张更清楚的流程图：
示例编写
父pom
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.cloud.work</groupId>
<artifactId>work-cloud</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>pom</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<java.version>1.8</java.version>
<spring-cloud-alibaba.version>2.2.0.RELEASE</spring-cloud-alibaba.version>
<spring-cloud.version>Hoxton.SR5</spring-cloud.version>
<spring-boot.version>2.3.0.RELEASE</spring-boot.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-alibaba-dependencies</artifactId>
<version>${spring-cloud-alibaba.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>${spring-boot.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
<modules>
<module>cloud-gateway</module>
</modules>
</project>依赖项目gateway的pom
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.cloud.work</groupId>
<artifactId>work-cloud</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<artifactId>cloud-gateway</artifactId>
<dependencies>
<!-- 引入 Spring Cloud Gateway 相关依赖，使用它作为网关，并实现对其的自动配置 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
</dependencies>
</project>application.yml
server:
port: 8081
spring:
cloud:
# Spring Cloud Gateway 配置项，对应 GatewayProperties 类
gateway:
# 路由配置项，对应 RouteDefinition 数组
routes:
- id: yudaoyuanma # 路由的编号
uri: https://www.baidu.com # 路由到的目标地址
predicates: # 断言，作为路由的匹配条件，对应 RouteDefinition 数组
- Path=/blog
filters:
- StripPrefix=1
- id: oschina # 路由的编号
uri: https://www.oschina.net # 路由的目标地址
predicates: # 断言，作为路由的匹配条件，对应 RouteDefinition 数组
- Path=/oschina
filters: # 过滤器，对请求进行拦截，实现自定义的功能，对应 FilterDefinition 数组
- StripPrefix=1启动项
package com.cloud.gateway;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class GatewayApplication {
public static void main(String[] args) {
SpringApplication.run(GatewayApplication.class, args);
}
}启动日志
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.3.0.RELEASE)
2020-11-29 13:12:34.666 INFO 19664 --- [ main] com.cloud.gateway.GatewayApplication : No active profile set, falling back to default profiles: default
2020-11-29 13:12:35.535 INFO 19664 --- [ main] o.s.cloud.context.scope.GenericScope : BeanFactory id=83925bed-0b21-326e-a5b0-784d1d4030ed
2020-11-29 13:12:35.639 INFO 19664 --- [ 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)
2020-11-29 13:12:35.640 INFO 19664 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerBeanPostProcessorAutoConfiguration$ReactiveLoadBalancerConfig' of type [org.springframework.cloud.client.loadbalancer.reactive.LoadBalancerBeanPostProcessorAutoConfiguration$ReactiveLoadBalancerConfig] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2020-11-29 13:12:35.644 INFO 19664 --- [ main] trationDelegate$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)
2020-11-29 13:12:35.851 WARN 19664 --- [ main] o.s.c.n.a.ArchaiusAutoConfiguration : No spring.application.name found, defaulting to 'application'
2020-11-29 13:12:35.857 WARN 19664 --- [ main] c.n.c.sources.URLConfigurationSource : No URLs will be polled as dynamic configuration sources.
2020-11-29 13:12:35.857 INFO 19664 --- [ 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.
2020-11-29 13:12:35.863 WARN 19664 --- [ main] c.n.c.sources.URLConfigurationSource : No URLs will be polled as dynamic configuration sources.
2020-11-29 13:12:35.863 INFO 19664 --- [ 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.
2020-11-29 13:12:43.204 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [After]
2020-11-29 13:12:43.204 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Before]
2020-11-29 13:12:43.204 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Between]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Cookie]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Header]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Host]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Method]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Path]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Query]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [ReadBodyPredicateFactory]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [RemoteAddr]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [Weight]
2020-11-29 13:12:43.205 INFO 19664 --- [ main] o.s.c.g.r.RouteDefinitionRouteLocator : Loaded RoutePredicateFactory [CloudFoundryRouteService]
2020-11-29 13:12:43.562 INFO 19664 --- [ main] o.s.s.c.ThreadPoolTaskScheduler : Initializing ExecutorService 'Nacso-Watch-Task-Scheduler'
2020-11-29 13:12:48.231 INFO 19664 --- [ main] o.s.b.web.embedded.netty.NettyWebServer : Netty started on port(s): 8888
2020-11-29 13:12:51.969 WARN 19664 --- [ main] c.a.c.n.registry.NacosServiceRegistry : No service to register for nacos client...
2020-11-29 13:12:52.005 INFO 19664 --- [ main] com.cloud.gateway.GatewayApplication : Started GatewayApplication in 21.601 seconds (JVM running for 22.549)
使用浏览器，访问 http://127.0.0.1:8888/blog，成功转发到目标 URI https://www.baidu.com，如下图所示：
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