public class CuratorDemo {  
    //ZooKeeper服務(wù)地址
    private static final String SERVER = "192.168.0.101:2181";
 
    //會(huì)話超時(shí)時(shí)間
    private static final int SESSION_TIMEOUT = 30000;
 
    //連接超時(shí)時(shí)間
    private static final int CONNECTION_TIMEOUT = 5000;
 
    /**
     * baseSleepTimeMs：初始的重試等待時(shí)間
     * maxRetries：最多重試次數(shù)
     *
     *
     * ExponentialBackoffRetry：重試一定次數(shù)，每次重試時(shí)間依次遞增
     * RetryNTimes：重試N次
     * RetryOneTime：重試一次
     * RetryUntilElapsed：重試一定時(shí)間
     */
    private static final RetryPolicy retryPolicy = new ExponentialBackoffRetry(1000, 3);  
    public static void main(String[] args) throws Exception {
        //創(chuàng)建 CuratorFrameworkImpl實(shí)例
        CuratorFramework client = CuratorFrameworkFactory.newClient(SERVER, SESSION_TIMEOUT, CONNECTION_TIMEOUT, retryPolicy);
 
        //啟動(dòng)
        client.start(); 
        System.out.println("連接成功！");
        Object o = client.getChildren().forPath("/");
        System.out.println(o);
    } 
}

public class ZookeeperBase{
	//zk集群地址(端口號(hào)為客戶端端口號(hào))
	private static final String CONNECT_ADDR = "192.168.241.127:2181,192.168.241.128:2181,192.168.241.129:2181";	
	//session 超時(shí)時(shí)間,單位毫秒
	private static final int SESSION_OUTTIME = 5000;	
	//用于阻塞程序執(zhí)行，直到zk成功連接后再發(fā)送繼續(xù)執(zhí)行信號(hào)，因?yàn)閦k建立連接是異步的，阻塞是防止程序在zk成功連接前被調(diào)用。
	private static final CountDownLatch contectedSemaphore = new CountDownLatch (1);	
	public static void main(String[] args)throws Exception{
		Zookeeper zk = new Zookeeper(CONNECT_ADDR,SESSION_OUTTIME,new Watcher()){
			@override
			public void process(WatcherEvent event){  //WatcherEvent為觀察者監(jiān)聽事件
			
				//獲取事件狀態(tài)（與客戶端連接狀態(tài)相關(guān)）
				/*
				* KeeperState:Disconneced        連接失敗 		 
				* KeeperState:SyncConnected	 連接成功	 		 
				* KeeperState:AuthFailed         認(rèn)證失敗		 
				* KeeperState:Expired            會(huì)話過期
				*/
				KeeperState keeperState = event.getState();
				
				//獲取事件類型(與zknode相關(guān))
				/*
				* EventType:NodeCreated            節(jié)點(diǎn)創(chuàng)建		 
				* EventType:NodeDataChanged        節(jié)點(diǎn)的數(shù)據(jù)變更		 
				* EventType:NodeChildrentChanged   子節(jié)點(diǎn)下的數(shù)據(jù)變更		 
				* EventType:NodeDeleted            節(jié)點(diǎn)刪除
				* EventType:None                   剛連接什么都沒做
				*/
				EventType eventType  = event.getType();
				
				//成功建立連接（固定寫法）
				if(KeeperState.SyncConnected == keeperState){
					if(EventType.None == eventType){
						//發(fā)送信號(hào)讓程序繼續(xù)執(zhí)行
						contectedSemaphore.countDown();
					}
				}				
			}
			
			//阻塞程序執(zhí)行
			contectedSemaphore.await();
			//創(chuàng)建節(jié)點(diǎn)
			//同步創(chuàng)建
			String newNode = zk.create("/testRoot","data".getBytes(),ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
			/*
			*參數(shù)1：節(jié)點(diǎn)路徑：/testRoot,原生api不允許遞歸創(chuàng)建節(jié)點(diǎn)，即沒有父節(jié)點(diǎn)不允許直接連帶父子節(jié)點(diǎn)一起創(chuàng)建。創(chuàng)建節(jié)點(diǎn)是要寫全路徑，例如：/testRoot/children。
			*參數(shù)2：節(jié)點(diǎn)內(nèi)容：內(nèi)容類型為字節(jié)數(shù)組，不支持存儲(chǔ)序列化對(duì)象，例如不支持將java對(duì)象序列化為json存儲(chǔ)，但可以使用java序列化框架，如hession或kyso。
			*參數(shù)3：權(quán)限控制：在對(duì)權(quán)限要求不嚴(yán)格情況下都使用OPEN_ACL_UNSAFE開放權(quán)限即可。
			*參數(shù)4：節(jié)點(diǎn)類型：提供了四種類型。
			*PERSISTENT 持久化節(jié)點(diǎn)
			*PERSISTENT SEQUENTIAL 持久順序節(jié)點(diǎn)
			*EPHEMERAL 臨時(shí)節(jié)點(diǎn)
			*EPHEMERAL SEQUENTIAL 臨時(shí)順序節(jié)點(diǎn)
			*/
		};	
	} 	
}