三个类：

ServiceAProvider

ServiceBProvider

ServiceConsumer

其中

ServiceAProvider提供的服务名service-A，指向IP为192.168.58.130

ServiceBProvider提供的服务名service-A，指向IP为192.168.58.131

当有消费者请求时，随机地选取service-A列表的服务器提供服务

ServiceConsumer 为消费者类

依赖：

<dependency>
			<groupId>org.apache.zookeeper</groupId>
			<artifactId>zookeeper</artifactId>
			<version>3.4.5-cdh5.1.0</version>
		</dependency>
		<dependency>
			<groupId>org.apache.helix</groupId>
			<artifactId>helix-core</artifactId>
			<version>0.6.4</version>
		</dependency>

github源码下载地址：

https://github.com/Bellonor/myhadoop2.x/tree/master/myhadoop2.x/src/main/java/com/jamesfen/zookeeper

详见下面的代码：

服务提供者ServiceAProvider类的源码为：

package com.jamesfen.zookeeper;
import java.net.InetAddress;
import org.I0Itec.zkclient.ZkClient;
public class ServiceAProvider {

	 private String serviceName = "service-A";
	   
	    //向zookeeper注册服务
	    public void init() throws Exception{
	        String serverList = "192.168.58.11:2181";
	        String PATH ="/configcenter";//根节点路径
	        ZkClient zkClient = new ZkClient(serverList);
	        boolean rootExists = zkClient.exists(PATH);
	        if(!rootExists){
	            zkClient.createPersistent(PATH);
	        }
	      //判断是否存在，不存在则创建服务节点
	        boolean serviceExists = zkClient.exists(PATH + "/" + serviceName);
	        if(!serviceExists){
	            zkClient.createPersistent(PATH + "/" + serviceName);
	        }
	        
	        //註冊當前服務
	        InetAddress addr =InetAddress.getLocalHost();
	        //String ip= addr.getHostAddress().toString();
	        String ip = "192.168.58.130";
	        
	        //創建當前服務器節點
	        zkClient.createEphemeral(PATH + "/" + serviceName + "/" + ip);
	        
	        System.out.println("提供的服务节点名称为："+PATH + "/" + serviceName + "/" + ip);
	    }
	    //提供服务
	    public void provide(){
	        
	    }
	    public static void main(String[]args) throws Exception {
	        ServiceAProvider service = new ServiceAProvider();
	        service.init();
	        
	        Thread.sleep(1000*60*60*24);
	    }

}

package com.jamesfen.zookeeper;
import java.net.InetAddress;
import org.I0Itec.zkclient.ZkClient;
public class ServiceBProvider {
   //服务名仍然为 A,这样是为了，一个服务名有两个台机器在服务，才能做负载均衡.
	private String serviceName = "service-A";
	   
    //向zookeeper注册服务
    public void init() throws Exception{
        String serverList = "192.168.58.11:2181";
        String PATH ="/configcenter";//根节点路径
        ZkClient zkClient = new ZkClient(serverList);
        boolean rootExists = zkClient.exists(PATH);
        if(!rootExists){
            zkClient.createPersistent(PATH);
        }
        
        boolean serviceExists = zkClient.exists(PATH + "/" + serviceName);
        if(!serviceExists){
            zkClient.createPersistent(PATH + "/" + serviceName);//創建服務節點
        }
        
        //註冊當前服務
        InetAddress addr =InetAddress.getLocalHost();
        //String ip= addr.getHostAddress().toString();
        String ip = "192.168.58.131";
        
        //創建當前服務器節點
        zkClient.createEphemeral(PATH + "/" + serviceName + "/" + ip);
        
        System.out.println("提供的服务节点名称为："+PATH + "/" + serviceName + "/" + ip);
    }
    //提供服务
    public void provide(){
        
    }
    public static void main(String[]args) throws Exception {
        ServiceBProvider service = new ServiceBProvider();
        service.init();
        
        Thread.sleep(1000*60*60*24);
    }

}

package com.jamesfen.zookeeper;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import org.I0Itec.zkclient.IZkChildListener;
import org.I0Itec.zkclient.ZkClient;
public class ServiceConsumer {

	private List<String> serverList = new ArrayList<String>();
	   
    private String serviceName ="service-A";
   
    //初始化服务地址信息
    public void init(){     
        String zkServerList ="192.168.58.11:2181";
        String SERVICE_PATH="/configcenter/"+serviceName;//服务节点路径
        ZkClient zkClient = new ZkClient(zkServerList);
        
        boolean serviceExists =zkClient.exists(SERVICE_PATH);
        if(serviceExists){
            serverList =zkClient.getChildren(SERVICE_PATH);
        }else{
            throw new RuntimeException("service not exist!");
        }
        
        //注册事件监听
        zkClient.subscribeChildChanges(SERVICE_PATH,new IZkChildListener(){
            //@Override
            public void handleChildChange(String parentPath, List<String> currentChilds)throws Exception{
                serverList = currentChilds;
            }      
        });
    }
   
   
    //消费服务
    public void consume(){
        //通过负责均衡算法，得到一台服务器进行调用
        int index = getRandomNum(0,1);      
        System.out.println("调用" + serverList.get(index)+"提供的服务：" + serviceName);
    }
   
    public int getRandomNum(int min,int max){  
        Random rdm = new Random();  
        return rdm.nextInt(max-min+1)+min;
    }  
   
    public static void main(String[] args)throws Exception {
        ServiceConsumer consumer = new ServiceConsumer();   
               
        consumer.init();
        consumer.consume();
        
        Thread.sleep(1000*60*60*24);
    }

}

使用zookeeper实现服务路由和负载均衡