Spring Cloud Gateway

什么是SpringCloud Gateway

SpringCloud GateWay是Spring官方基于Spring5.0, SpringBoot2.0,SpringWebFlux, Project Reactor技术开发的高性能网关，旨在为微服务架构提供简单、有效且统一的API 路由管理方式。
整体工作架构如下：

核心组件说明

• Route（路由）：代表转发规则，由id, 目标url, 一组断言工厂和一组过滤器组成。如果断言为真，说明请求的URL与配置的路由匹配
• Predict（断言）：断言函数，与Java8中的Predict语义一致
• Filter（过滤器）：代表一个标准的Spring WebFilter. Gateway中有2种Filter，GlobalFilter，全局范围生效，GatewayFilter,在路由上生效。

工作原理

简单使用

依赖引入

<?xml version="1.0" encoding="UTF-8"?>
<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>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example.springcloud</groupId>
    <artifactId>gateway</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springcloud-gateway</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>2021.0.1</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
        <!-- 如果需要把Gateway注册到Eureka上，引入eureka-client -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </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>
        </dependencies>
    </dependencyManagement>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

路由配置

代码方式

/***
* 通过代码API配置路由
* @param builder
* @return
*/
@Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
    return builder.routes().route(r ->
                 r.path("/greet") // 满足Predict
                 .filters(f -> f.filter(new CustomGateFilter(), 0))
                 .uri("http://localhost:8080/greet")) // 转发到对应的URI
        .build();
    }
public static class CustomGateFilter implements GatewayFilter {
        private static final Log log = LogFactory.getLog(GatewayFilter.class);
        private static final String countStartTime = "countStartTime";
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            exchange.getAttributes().put(countStartTime, System.currentTimeMillis());
            return chain.filter(exchange).then(
                    Mono.fromRunnable(() -> {
                        Long startTime = exchange.getAttribute(countStartTime);
                        if (startTime != null) {
                            log.info(exchange.getRequest().getURI().getRawPath() + ":" + (System.currentTimeMillis() - startTime));
                        }
                    })
            );
        }
    }

YML配置方式

spring:
  application:
    name: spring-cloud-gateway
  cloud:
    gateway:
      routes:
        - id: taobao_route
          uri: http://www.taobao.com
          predicates:
            - Path=/tb
      discovery:
        locator:
          enabled: true
          lowerCaseServiceId: true