zookeeper客户端 curator的使用

curator简介

Curator是Netflix公司开源的一个Zookeeper客户端，与Zookeeper提供的原生客户端相比，Curator的抽象层次更高，提供了各种应用场景的实现封装，fluent风格的API增加了代码的优雅性，简化了Zookeeper客户端的开发量。

public class CuratorCreateSessionDemo {
	private final static String CONNECTSTRING="192.168.74.131:2181,192.168.74.132:2181,192.168.74.133:2181";
	public static void main(String[] args) {
		 //创建会话的两种方式
		CuratorFramework curatorFramework = CuratorFrameworkFactory.newClient(CONNECTSTRING, 5000,5000,new ExponentialBackoffRetry(1000, 3));//ExponentialBackoffRetry 衰减重试
		curatorFramework.start();
		
		 //fluent风格
		CuratorFramework curatorFramework2 = CuratorFrameworkFactory.builder().connectString(CONNECTSTRING).sessionTimeoutMs(5000).retryPolicy(new ExponentialBackoffRetry(1000, 3)).build();
		curatorFramework2.start();
		System.out.println("success");
	}
}

curator创建 删除  查询 更新  异步   事务（事务是curator独有的）代码：

public class CuratorOperatorDemo {
	public static void main(String[] args) throws Exception {
		CuratorFramework curatorFramework = CuratorClientUtils.getInstance();
		System.out.println("连接成功....");

		// flunt风格

		/**
		 * 创建节点 可以递归创建
		 */
		/*
		 * try { String result =
		 * curatorFramework.create().creatingParentsIfNeeded().withMode(
		 * CreateMode.PERSISTENT).forPath("/c/cc/ccc", "123".getBytes()); }
		 * catch (Exception e) { // TODO: handle exception }
		 */

		/**
		 * 删除节点 可以递归删除
		 */
		/*
		 * try {
		 * curatorFramework.delete().deletingChildrenIfNeeded().forPath("/c"); }
		 * catch (Exception e) { // TODO: handle exception }
		 */

		/**
		 * 查询
		 */
		/*
		 * try { Stat stat = new Stat(); byte[]
		 * bytes=curatorFramework.getData().storingStatIn(stat).forPath(
		 * "/zkclient"); System.out.println(new String(bytes)+"-->stat:"+stat);
		 * } catch (Exception e) { }
		 */

		/**
		 * 更新
		 */
		/*
		 * try { Stat stat = curatorFramework.setData().forPath("/zookeeper",
		 * "666".getBytes()); byte[]
		 * bytes=curatorFramework.getData().storingStatIn(stat).forPath(
		 * "/zkclient"); System.out.println(new String(bytes));
		 * System.out.println("stat:"+stat); } catch (Exception e) { // TODO:
		 * handle exception }
		 */

		/** 
		 * 异步操作   创建节点与set值异步进行
		 */
		/*ExecutorService service = Executors.newFixedThreadPool(1);
		final CountDownLatch countDownLatch = new CountDownLatch(1);
		try {
			System.out.println(1);
			curatorFramework.create().creatingParentsIfNeeded().withMode(CreateMode.PERSISTENT)
					.inBackground(new BackgroundCallback() {
						public void processResult(CuratorFramework curatorFramework, CuratorEvent curatorEvent)
								throws Exception {
							// TODO Auto-generated method stub
							System.out.println(Thread.currentThread().getName() + "->resultCode:"
									+ curatorEvent.getResultCode() + "->" + curatorEvent.getType());
							countDownLatch.countDown();
						}
					},service).forPath("/b","111".getBytes());
		} catch (Exception e) {
		}
		countDownLatch.await();
        service.shutdown();*/
        
        
		/**
		 * 事务操作
		 */
		/*try {
            Collection<CuratorTransactionResult> resultCollections=curatorFramework.inTransaction().create().forPath("/trans","111".getBytes()).and().
                    setData().forPath("/bzy","111".getBytes()).and().commit();
            for (CuratorTransactionResult result:resultCollections){
                System.out.println(result.getForPath()+"->"+result.getType());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }*/
        
	}
}

curator创建监听

public class CuratorEventDemo {
	/**
	 * 三种watcher来做节点监听
	 * pathcache 监视一个路径下子节点的创建 删除 数据更新
	 * nodecache 监视一个节点的创建 更新 删除
	 * treecache pathcache+nodecache的合体(监视路径下的创建 更新 删除)
	 * @throws Exception 
	 */
	public static void main(String[] args) throws Exception {
		CuratorFramework curatorFramework = CuratorClientUtils.getInstance();
		/**
		 * 节点变化nodecache
		 */
		NodeCache nodeCache = new NodeCache(curatorFramework,"/zkclient",false);
		nodeCache.start(true);
		nodeCache.getListenable().addListener(()-> System.out.println("节点数据发生变化,变化后的结果" +
                "："+new String(nodeCache.getCurrentData().getData())));
		curatorFramework.setData().forPath("/zkclient","bzy666".getBytes());
		
		
		/**
		 * pathcache 子节点数据变化
		 */
		PathChildrenCache cache=new PathChildrenCache(curatorFramework,"/zkclient",true);
        cache.start(PathChildrenCache.StartMode.POST_INITIALIZED_EVENT);
        // Normal / BUILD_INITIAL_CACHE /POST_INITIALIZED_EVENT

        cache.getListenable().addListener((curatorFramework1,pathChildrenCacheEvent)->{
            switch (pathChildrenCacheEvent.getType()){
                case CHILD_ADDED:
                    System.out.println("增加子节点");
                    break;
                case CHILD_REMOVED:
                    System.out.println("删除子节点");
                    break;
                case CHILD_UPDATED:
                    System.out.println("更新子节点");
                    break;
                default:break;
            }
        });
		
        curatorFramework.create().withMode(CreateMode.PERSISTENT).forPath("/zkclient","zkclient".getBytes());
        TimeUnit.SECONDS.sleep(1);
        System.out.println("1");
        curatorFramework.create().withMode(CreateMode.EPHEMERAL).forPath("/zkclient/zkclient1","1".getBytes());
        TimeUnit.SECONDS.sleep(1);
        System.out.println("2");

        curatorFramework.setData().forPath("/zkclient/zkclient1","222".getBytes());
        TimeUnit.SECONDS.sleep(1);
        System.out.println("3");

        curatorFramework.delete().forPath("/zkclient/zkclient1");
        System.out.println("4");

        System.in.read();
	}
}