Spring Cloud Gateway + Nacos 实现动态路由

1、maven 依赖

主要依赖

		<!-- 网关 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>

案件差不多完整主要依赖

		<!--Spring boot 依赖(微服务基础)-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <!--使用exclusions标签来标明要排除的包-->
            <!--排除logback-->
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!--Web 服务相关-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- 生成配置元数据，比如你平常在yml文件里面配置 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>

        <!--单元测试依赖,子工程中需要单元测试时,不需要再次引入此依赖了-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!--bootstrap 相关-->
        <!--SpringBoot2.4.x之后默认不加载bootstrap.yml文件，需要在pom里加上依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-bootstrap</artifactId>
			<version>4.0.0</version>
        </dependency>
        
        <!--服务的注册和发现-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>

        <!--lombok 依赖,子工程中假如需要lombok,不需要再引入-->
        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.30</version>
            <scope>provided</scope>
        </dependency>
        
		<!-- 网关 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>

2、bootstrap.yml配置

server:
  port: 9999
  tomcat:
    max-http-form-post-size: -1
    max-threads: 500
    min-spare-threads: 50
  servlet:
    context-path: /
spring:
  main:
    web-application-type: reactive
     #当遇到同样名字的时候，是否允许覆盖注册
    allow-bean-definition-overriding: true 
  profiles:
    active: ${SYS_ENV:} # local:本地，dev：测试，uat:uat
  application:
    name: gateway-service
  cloud:
    nacos:
      # 配置中心#
      config:
        username: ${NACOS_USER:nacos}
        password: ${NACOS_PASSWORD:nacos}
        server-addr: ${NACOS_IP:nacos.com}:${NACOS_POST:8848}
        namespace: ${NACOS_NAMESPACE:}
        file-extension: yml
        refresh-enabled: true
        override-none: true  #本地配置优先
        shared-configs:
          - application.${spring.cloud.nacos.config.file-extension} # 配置文件名-Data Id
    # 路由网关配置
    gateway:
      # 启用了自动根据服务名建立路由
      discovery:
        locator:
          enabled: true
          lower-case-service-id: true

# 动态路由配置
config:
  # 动态
  gateway-route:
    # nacos 配置dataId
    dataId: gateway-router
    # nacos服务地址
    server-addr: ${spring.cloud.nacos.config.server-addr}
    # 命名空间
    namespace: ${spring.cloud.nacos.config.namespace}

3、nacos 中心网关路由配置

[
    {
        "id": "auth-service",
        "uri": "lb://auth-service",
        "predicates": [
            {
                "args": {
                    "pattern": "/auth-service/**"
                },
                "name": "Path"
            }
        ],
        "filters": [
            {
                "args": {
                    "parts": 1
                },
                "name": "StripPrefix"
            }
        ],
        "order": 1
    },
    {
        "id": "user-service",
        "uri": "lb://user-service",
        "predicates": [
            {
                "args": {
                    "pattern": "/user-service/**"
                },
                "name": "Path"
            }
        ],
        "filters": [
            {
                "args": {
                    "parts": 1
                },
                "name": "StripPrefix"
            }
        ],
        "order": 2
    }
]

4、配置文件 GatewayRouteConfig

import cn.hutool.core.lang.Assert;
import cn.hutool.core.util.StrUtil;
import com.alibaba.fastjson.JSONObject;
import com.alibaba.nacos.api.NacosFactory;
import com.alibaba.nacos.api.config.ConfigService;
import com.alibaba.nacos.api.config.listener.Listener;
import com.alibaba.nacos.api.exception.NacosException;
import jakarta.annotation.PostConstruct;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteDefinitionWriter;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;

import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.concurrent.Executor;

/**
 * 类描述：通过Nacos的配置动态更新网管路由
 * 
 *     ApplicationEventPublisherAware 是由 Spring 提供的用于为 Service 注入 ApplicationEventPublisher 事件发布器的接口，使用这个接口，
 *     我们自己的 Service 就拥有了发布事件的能力。用户注册后，不再是显示地调用其他的业务 Service，而是发布一个用户注册事件。
 * 
 *
 */
@Slf4j
@RefreshScope
@Component
public class GatewayRouteConfig implements ApplicationEventPublisherAware {
    /** 常量 */
    private static final String PROPERTIES_SERVER_ADDR = "serverAddr";
    private static final String PROPERTIES_NAMESPACE = "namespace";
    private static final String PROPERTIES_GROUP = "group";

    /** nacos 配置dataId */
    @Value("${config.gateway-route.dataId:gateway-router}")
    private String dataId = "gateway-routes";

    /** nacos 配置group */
    @Value("${config.gateway-route.group:DEFAULT_GROUP}")
    private String group = "DEFAULT_GROUP";

    /** nacos 配置地址 */
    @Value("${config.gateway-route.server-addr}")
    private String serverAddr;

    /** nacos 命名空间 */
    @Value("${config.gateway-route.namespace}")
    private String namespace;

    /** 已加载的路由id集合 */
    private static final List<String> ROUTE_LIST = new ArrayList<>();

    private final RouteDefinitionWriter routeDefinitionWriter;

    /** 事件发布器 */
    private ApplicationEventPublisher applicationEventPublisher;

    /**
     * 方法描述： 构造函数
     *
     * @param routeDefinitionWriter 路由定义写对象
     */
    public GatewayRouteConfig(RouteDefinitionWriter routeDefinitionWriter) {
        this.routeDefinitionWriter = routeDefinitionWriter;
    }

    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.applicationEventPublisher = applicationEventPublisher;
    }

    /**
     * 方法描述： 从Nacos的配置中加载动态路由
     *
     */
    @PostConstruct
    public void loadRouteFromNacosAndListener() {
        try {
            ConfigService configService = NacosFactory.createConfigService(getProperties());
            // 程序启动时调用Nacos的配置进行路由加载
            String initConfigInfo = configService.getConfig(dataId, group, 5000);
            addRouteAndPublish(initConfigInfo);

            // 添加监听路由变化
            addListener(configService);
        } catch (NacosException e) {
            log.error("加载路由配置错误，详情：", e);
        }
    }

    /**
     * 方法描述： 添加监听
     *
     * @param cs 配置服务对象
     */
    private void addListener(ConfigService cs) throws NacosException {
        // 添加监听
        cs.addListener(dataId, group, new Listener() {
            @Override
            public void receiveConfigInfo(String configInfo) {
                // 将监听到的路由加载到路由定义器中
                addRouteAndPublish(configInfo);
            }

            @Override
            public Executor getExecutor() {
                return null;
            }
        });
    }

    /**
     * 方法描述： Nacos配置属性
     *
     * @return {@link Properties}
     */
    private Properties getProperties() {
        Assert.notBlank(serverAddr, "Nacos的服务地址为空了！");
        Properties properties = new Properties();
        properties.put(PROPERTIES_SERVER_ADDR, serverAddr);
        if (StrUtil.isNotBlank(namespace)) {
            properties.put(PROPERTIES_NAMESPACE, namespace);
        }
        if (StrUtil.isNotBlank(group)) {
            properties.put(PROPERTIES_GROUP, group);
        }
        return properties;
    }

    /**
     * 添加并发布配置的路由
     *
     * @param configInfo 路由配置字符串；格式：JSON数组
     */
    private void addRouteAndPublish(String configInfo) {
        // 加载前需要清空有存在的路由
        clearRoute();
        // 解析从Nacos配置中读取的路由配置信息
        List<RouteDefinition> gatewayRouteDefinitions = JSONObject.parseArray(configInfo, RouteDefinition.class);
        for (RouteDefinition routeDefinition : gatewayRouteDefinitions) {
            // 将路由写到定义器中
            routeDefinitionWriter.save(Mono.just(routeDefinition)).subscribe();
            // 将路由id加入内存集合中
            ROUTE_LIST.add(routeDefinition.getId());
        }

        // 刷新路由定义器
        this.applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this.routeDefinitionWriter));
    }

    /**
     * 方法描述： 清空已存在的路由
     */
    private void clearRoute() {
        ROUTE_LIST.forEach(id -> this.routeDefinitionWriter.delete(Mono.just(id)).subscribe());
        ROUTE_LIST.clear();
    }
}