参考文档：Spring Gateway官方文档 , 玹霖的博客

1.Spring Gateway简介

Spring Cloud Gateway是Spring官方基于Spring 5.0，Spring Boot 2.0和Project Reactor等技术开发的网关，Spring Cloud Gateway旨在为微服务架构提供一种简单而有效的统一的API路由管理方式。Spring Cloud Gateway作为Spring Cloud生态系中的网关，目标是替代Netflix ZUUL，其不仅提供统一的路由方式，并且基于Filter链的方式提供了网关基本的功能，例如：安全，监控/埋点，和限流等。

2.Spring Gateway工作原理

Spring Gateway工作结构图

spring_cloud_gateway_diagram.png

3.Spring Gateway配置和使用

由于项目使用maven模块化配置，Springboot版本为：2.0.3.RELEASE, SpringCloud版本为：Finchley.RELEASE

• pom配置：

<dependencies>
      <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-contract-stub-runner</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-web</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-consul-discovery</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-web</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <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>

请注意：不要引入spring-boot-starter-web包，会导致Gateway启动抛出异常

Spring Gateway支持两种方式提供路由服务，其一是配置文件启用，其二则是通过代码达到目的

• application.yml配置实现

spring:
  application:
    name: xxxx
  cloud:
    consul:
      host: localhost
      port: 8500
      discovery:
        enabled: true
        instance-id: ${spring.application.name}:${spring.cloud.client.ip-address}:${server.port}
        service-name: xxxx
        prefer-ip-address: true
    gateway:
      discovery:
        locator:
          enabled: true
      routes:
      # This route rule used to forward request to activity server
      - id: activity-route
        uri: lb://activity
        predicates:
        - Path=/activity/**
        filters:
        - StripPrefix=1

注意：Gateway默认转发是全路径的，设置StripPrefix=1表示从二级url路径转发，即http://localhost:port/activity/test将会转发到http://{activity}/test

• 代码实现

@Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
        return builder.routes()
                .route(r -> r.path("/activity/**")
                        .filters(f -> f.stripPrefix(1).filter(new TestGetWayFilter()).addResponseHeader("X-Response-Default-Foo", "Default-Bar"))
                        .uri("lb://activity")
                        .order(0)
                        .id("activity-route")
                )
                .build();
 }