学习Curator（二）

        主要从官网学习这个框架，主要想用他来得到集群中的领导者，通过这个框架感觉都变简单了。

	public static void main(String[] args) throws Exception {
		RetryPolicy retryPolicy=new ExponentialBackoffRetry(1000, Integer.MAX_VALUE);
		String connectString="10.1.15.24:2181";
		CuratorFramework client = CuratorFrameworkFactory.newClient(connectString, retryPolicy);
		client.start();
			System.out.println("zookeeper start");
			if(client.checkExists().forPath("/head")==null){
				client.create().forPath("/head","hello world".getBytes());
//				System.out.println(client.getData().watched().inBackground().forPath("/head"));
				byte[] value=client.getData().watched().forPath("/head");
				
				System.out.println(new String(value!=null?value:new byte[0]));
				client.delete().inBackground().forPath("/head");  				
			}else {
				client.delete().inBackground().forPath("/head");  		
				System.err.println("删除已经存在的znode");
			}
			LeaderSelectorListener listener = new LeaderSelectorListenerAdapter() {
				
				public void takeLeadership(CuratorFramework client) throws Exception {
					System.out.println("I'm leader");	
				}
			};			
			LeaderSelector leader = new LeaderSelector(client, "/leader", listener);
			leader.autoRequeue();
			leader.start();
	}

     纪录一下方便以后自己学习。