netty-tomcat-sample/rpc-client-v3/src/main/java/cn/hhj/disovery/impl/ServiceDiscoveryWithZk.java

package cn.hhj.disovery.impl;

import cn.hhj.balance.LoadBalanceStrategy;
import cn.hhj.balance.RandomLoadBalance;
import cn.hhj.config.ZkConfig;
import cn.hhj.disovery.IServiceDiscovery;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.cache.PathChildrenCache;
import org.apache.curator.framework.recipes.cache.PathChildrenCacheListener;
import org.apache.curator.retry.ExponentialBackoffRetry;

import java.util.ArrayList;
import java.util.List;

public class ServiceDiscoveryWithZk implements IServiceDiscovery {
    private CuratorFramework curatorFramework =null;
    List<String> serviceRepos=new ArrayList<>(); //服务地址的本地缓存

    {
        //初始化zookeeper的连接， 会话超时时间是5s，衰减重试
        curatorFramework = CuratorFrameworkFactory.builder().
                connectString(ZkConfig.CONNECTION_STR).sessionTimeoutMs(5000).
                retryPolicy(new ExponentialBackoffRetry(1000, 3)).
                namespace("registry")
                .build();
        curatorFramework.start();
    }

    @Override
    public List<String> discovery(String serviceName) {
        String path="/"+serviceName;
        if(serviceRepos.isEmpty()) {
            try {
                serviceRepos = curatorFramework.getChildren().forPath(path);
                registryWatch(path);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return serviceRepos;
    }

    private void registryWatch(String path) throws Exception {
        PathChildrenCache nodeCache=new PathChildrenCache(curatorFramework,path,true);
        PathChildrenCacheListener cacheListener=(curatorFramework1, pathChildrenCacheEvent)->{
            System.out.println("客户端收到变更节点的事件");
            serviceRepos=curatorFramework1.getChildren().forPath(path);
        };
        nodeCache.getListenable().addListener(cacheListener);
        nodeCache.start();
    }
}