Spring Cloud Gateway入门

1、什么是Spring Cloud Gateway
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生态系统中的网关，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 Cloud Gateway入门案例
2.1 创建maven工程，pom.xml文件

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.lynch</groupId>
    <artifactId>spring-cloud-gateway</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </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>

2.2 Spring Cloud Gateway主程序

package com.lynch;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
import org.springframework.context.annotation.Bean;

/**
 * Spring Cloud Gateway主程序
 *
 * @author Lynch
 */
@SpringBootApplication
public class Application {
    @Bean
    public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
        return builder.routes()
                // basic proxy
                .route(r -> r.path("/baidu")
                .uri("http://baidu.com:80/"))
                .build();
    }

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

2.3 编写application.yml文件

server:
  port: 8080
spring:
  application:
    name: spring-cloud-gateway
  cloud:
    gateway:
      routes:
      - id: xujin_route
        uri: http://www.xujin.org:80/
        predicates:
        - Path=/xujin

logging:
  level:
    org.springframework.cloud.gateway: TRACE
    org.springframework.http.server.reactive: DEBUG
    org.springframework.web.reactive: DEBUG
    reactor.ipc.netty: DEBUG

2.4 基本代理路由配置等同写法
Spring Cloud Gateway提供了两种配置路由规则的方法

第一:通过@Bean自定义RouteLocator

    @Bean
    public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
        return builder.routes()
                // basic proxy
                .route(r -> r.path("/baidu")
                .uri("http://baidu.com:80/"))
                .build();
    }

第二:通过属于文件或者yml文件配置

spring:
  cloud:
    gateway:
      routes:
      - id: xujin_route
        uri: http://www.xujin.org:80/
        predicates:
        - Path=/xujin

2.5 运行测试
访问http://localhost:8080/baidu，路由转发到http://www.baidu.com
访问http://localhost:8080/xujin，路由转发到http://xujin.orgyml