详解自动注册Gateway网关路由配置

spring:
  application:
    name: item-order
  cloud:
    nacos:
      server-addr: 127.0.0.1:8848
      username: nacos
      password: nacos
      discovery:
        metadata:
          route.enable: true
          route.prefix: 1
          route.path: /order/**

import com.alibaba.cloud.nacos.discovery.NacosServiceDiscovery;
import com.alibaba.fastjson.JSON;
import com.alibaba.nacos.api.exception.NacosException;
import lombok.extern.slf4j.Slf4j;
import org.example.gateway.base.GatewayRouteDefinition;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.event.HeartbeatEvent;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.event.EventListener;
import java.util.List;
import java.util.Map;
import java.util.Objects;
/**
 * 自动注册网关路由配置
 * 通过注册中心的心跳机制实时查询是否注册
 *
 * @author 苦瓜不苦
 * @date 2022/11/15 14:19
 **/
@Slf4j
@Configuration
public class RouteRegisterConfig {
    // nacos服务发现
    private final NacosServiceDiscovery nacosServiceDiscovery;
    // 自定义的ApplicationEventPublisherAware子类，里面实现了save()和delete()方法
    private final GatewayRouteConfig gatewayRouteConfig;
    public RouteRegisterConfig(NacosServiceDiscovery nacosServiceDiscovery, GatewayRouteConfig gatewayRouteConfig) {
        this.nacosServiceDiscovery = nacosServiceDiscovery;
        this.gatewayRouteConfig = gatewayRouteConfig;
    }
    // @EventListener事件监听注解，监听HeartbeatEvent心跳机制
    @EventListener(classes = HeartbeatEvent.class)
    public void eventListen(ApplicationEvent applicationEvent) {
        try {
            // 根据当前服务分组查询注册的所有服务名
            List<String> serviceList = nacosServiceDiscovery.getServices();
            if (Objects.isNull(serviceList) || serviceList.size() <= 0) {
                return;
            }
            // 循环所有服务获取服务信息
            for (String service : serviceList) {
                // 判断是否注册路由，MAP对象记录的是配置成功的路由，通过服务ID来判断唯一性
                if (gatewayRouteConfig.MAP.containsKey(service)) {
                    continue;
                }
                // 获取当前服务ID所有的节点
                List<ServiceInstance> instanceList = nacosServiceDiscovery.getInstances(service);
                if (Objects.isNull(instanceList) || instanceList.size() <= 0) {
                    continue;
                }
                // 获取指定服务ID的第一个节点，是否需要遍历所有，根据实际情况决定，因为会存在一个微服务多实例节点
                ServiceInstance instance = instanceList.get(0);
                // 获取当前实例节点的元数据，主要是获取到上面所配置的信息
                Map<String, String> metadata = instance.getMetadata();
                // 判断是否开启注册路由
                if ("true".equals(metadata.get("route.enable"))) {
                    // 定制路由JSON模板
                    String template = "{\"filters\":[{\"name\":\"StripPrefix\",\"args\":{\"_genkey_0\":\"{StripPrefix}\"}}],\"id\":\"{id}\",\"uri\":\"lb://{id}\",\"order\":0,\"predicates\":[{\"name\":\"Path\",\"args\":{\"_genkey_0\":\"{Path}\"}}]}";
                    // 替换模板中的数据
                    template = template.replace("{id}", service)
                            .replace("{Path}", metadata.getOrDefault("route.path", "/**"))
                            .replace("{StripPrefix}", metadata.getOrDefault("route.prefix", "0"));
                    GatewayRouteDefinition definition = JSON.parseObject(template, GatewayRouteDefinition.class);
                    // 调用注册路由方法
                    gatewayRouteConfig.save(definition);
                    log.info("服务节点 {} 注册路由成功, 路由信息 \n {}", service, JSON.toJSONString(definition));
                }
            }
        } catch (NacosException e) {
            log.error("注册中心心跳机制监听失败\n", e);
        }
    }
}