SpringCloud Gateway 通过 Nacos 配置动态路由 (代码片段)

package com.xxx.jarvis.cloud.gateway.core.components;

import com.alibaba.fastjson.JSON;
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 lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
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 javax.annotation.PostConstruct;
import javax.annotation.Resource;
import javax.validation.constraints.NotNull;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.concurrent.Executor;

/**
 * 动态路由组件
 * <pre>
 *     监听Nacos配置文件的变化, 把配置文件的变更后的数据动态写入, 达到不重启Gateway, 也可以配置路由的要求
 *     - java 使用nacos config: @link: https://nacos.io/zh-cn/docs/sdk.html
 * </pre>
 * @author mao
 * @date 10/06/2020 14:52
 */
@Slf4j
@Component
public class DynamicRouteComponent implements ApplicationEventPublisherAware {
    @Value("${spring.cloud.nacos.config.server-addr}")
    private String serverAddr;

    @Value("${jarvis.nacos.global.group}")
    private String group;

    @Value("${jarvis.gateway-router-data-id}")
    private String routeConfigDataId;

    @Value("${jarvis.nacos.global.namespace}")
    private String namespace;

    @Resource
    private RouteDefinitionWriter routeDefinitionWriter;

    private ApplicationEventPublisher applicationEventPublisher;

    private static final List<String> ROUTE_LIST = new ArrayList<>();

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

    @PostConstruct
    public void dynamicRouteListener() {
        try {
            Properties properties = new Properties();
            properties.put("serverAddr", serverAddr);
            properties.put("namespace", namespace);
            ConfigService configService = NacosFactory.createConfigService(properties);

            // 程序首次启动, 并加载初始化路由配置
            String initConfigInfo = configService.getConfig(routeConfigDataId, group, 5000);
            addAndPublishBatchRoute(initConfigInfo);

            configService.addListener(routeConfigDataId, group, new Listener() {
                @Override
                public void receiveConfigInfo(String configInfo) {
                    addAndPublishBatchRoute(configInfo);
                }

                @Override
                public Executor getExecutor() {
                    return null;
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 清空所有路由
     */
    private void clearRoute() {
        for(String id : ROUTE_LIST) {
            this.routeDefinitionWriter.delete(Mono.just(id)).subscribe();
        }
        ROUTE_LIST.clear();
    }

    /**
     * 添加单条路由信息
     * @param definition RouteDefinition
     */
    private void addRoute(RouteDefinition definition) {
        routeDefinitionWriter.save(Mono.just(definition)).subscribe();
        ROUTE_LIST.add(definition.getId());
    }

    /**
     * 批量 添加及发布 路由
     * @param configInfo 配置文件字符串, 必须为json array格式
     */
    private void addAndPublishBatchRoute(String configInfo) {
        try {
            clearRoute();
            List<RouteDefinition> gatewayRouteDefinitions = JSONObject.parseArray(configInfo, RouteDefinition.class);
            for (RouteDefinition routeDefinition : gatewayRouteDefinitions) {
                addRoute(routeDefinition);
            }
            publish();
            log.info("Dynamic config gateway route finished. {}", JSON.toJSONString(gatewayRouteDefinitions));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void publish() {
        this.applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this.routeDefinitionWriter));
    }
}