Java zookeeper 分布式开发

1、安装zookeeper

 下载zk http://archive.cloudera.com/cdh5/cdh/5/ 

 配置文件

tickTime=2000
initLimit=10
syncLimit=5
# zk数据保存目录 
dataDir=/usr/local/zookeeper/data
clientPort=2181

 启动：

bin/zkServer.sh start 

客户端命令行链接：

bin/zkCli.sh

2、拷贝zookeeper下的jar包，到应用程序，并使用maven引入相关jar包

<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-api</artifactId>
	<version>1.7.25</version>
</dependency>


<dependency>
	<groupId>org.apache.zookeeper</groupId>
	<artifactId>zookeeper</artifactId>
	<version>3.4.5-cdh5.10.0</version>
	<scope>system</scope>
	<systemPath>${project.basedir}/lib/zookeeper-3.4.5-cdh5.10.0.jar</systemPath>
</dependency>

  java 代码

	
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZookeeperContext {

	protected static Logger logger = LoggerFactory.getLogger("zk");
	
	public final int SESSION_TIME_OUT = 2000;
	public ZooKeeper zk;
	/**
	 * 判断zk的链接链接状态
	 * */
	public boolean isConnected(){
		return zk.getState() == ZooKeeper.States.CONNECTED;
	}
	
	/**
	 * 创建zk链接
	 * **/
	public ZookeeperContext(String connectString) {
		try {
                    /**
			 * connectString 链接zookeeper的Ip和端口，多个用逗号隔开例如：
			 * 10.0.0.104:2181,10.0.0.105:2181 sessionTimeout
			 * 客户端和zookeeper链接断开后，数据最长保存的时间 watcher 监控回调，服务器数据修改会回调
			 */
			zk = new ZooKeeper(connectString, SESSION_TIME_OUT, new ZookeeperWatcher());
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * zk监听，如果服务器端有什么变化到这里接收
	 * 并继续添加监听
	 * */
	public class ZookeeperWatcher implements Watcher {
		@Override
		public void process(WatchedEvent event) {
			try {
				
				if(null != event.getPath()){
					System.out.println( event );
					if(event.getType() == EventType.NodeChildrenChanged){
						zk.getChildren(event.getPath(), true) ; 
					}else{
						zk.getData(event.getPath(), true, null) ; 
					}
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}
	
	/**
	 * 在zk创建数据
	 * */
	public void setData(String path,byte[]data , CreateMode createMode){
		try {
			if(zk.exists(path, false) == null){
				zk.create(path, data, Ids.OPEN_ACL_UNSAFE, createMode) ;
			}else{
				zk.setData(path,data,-1);
			}
			zk.getChildren(path, true) ;
		} catch (Exception e) {
			logger.error("setData", e );
		}
	}
	
	public static void main(String[] args)throws Exception {
		ZookeeperContext context = new ZookeeperContext("10.0.0.104:2181"); 
		
		while (!context.isConnected()) {
			Thread.sleep(3000);
		}
		context.setData("/root", "1".getBytes(),CreateMode.PERSISTENT);
		context.setData("/root/hpgary", "gg".getBytes() , CreateMode.EPHEMERAL);
		System.err.println("eee");
		System.in.read() ;
	}

}