1：curator中的三種監聽器實現
第一種是可以監控本節點中節點的建立，刪除，資料的修改。僅限於此節點本身
public class CuratorNodeCacheListener {
private static final String PATH =”/example/cache”;
private static final String zkStr=”master:2181,worker1:2181,worker2:2181”;
private static InterProcessMutex lock;

public static void main(String [] args) throws Exception{
    CuratorFramework client = null;
    NodeCache cache = null;
    try
    {
        client = CuratorFrameworkFactory.newClient(zkStr, new ExponentialBackoffRetry(1000, 3));
        client.start();
        cache = new NodeCache(client,PATH);
        cache.start();
        processCommand(cache);
    }
    finally
    {
        CloseableUtils.closeQuietly(cache);
        CloseableUtils.closeQuietly(client);
    }
}

private static void processCommand( NodeCache cache) {
    boolean isDone=false;
    try{
        addListener(cache);
        while(!isDone){
            Thread.sleep(Long.MAX_VALUE);
        }
    }catch (Exception e){

    }finally {

    }

}

private static void addListener(final NodeCache cache)
{
    // a PathChildrenCacheListener is optional. Here, it's used just to log changes
    NodeCacheListener listener=new NodeCacheListener() {
        public void nodeChanged() throws Exception {
            System.out.println("catch node data change");
            ChildData childData=cache.getCurrentData();
            if(childData==null){
               System.out.println("data is delete    childData="+childData);
            }else{
                System.out.println("data is update    data="+childData.getData().toString());
            }
        }
    };
    cache.getListenable().addListener(listener);
}
 

}

這種監聽器主要是監聽某一路徑對應的結點下直接子節點的建立，刪除，修改資料，僅限於直接節點，再往下的結點就不能監控了
public class CuratorPathChildListener {
private static final String PATH = “/example/cache”;
private static final String zkStr=”master:2181,worker1:2181,worker2:2181”;
public static void main(String[] args) throws Exception{
CuratorFramework client = null;
PathChildrenCache cache = null;
try
{
client = CuratorFrameworkFactory.newClient(zkStr, new ExponentialBackoffRetry(1000, 3));
client.start();
cache = new PathChildrenCache(client, PATH, true);
cache.start();
processCommand(cache);
}
finally
{
CloseableUtils.closeQuietly(cache);
CloseableUtils.closeQuietly(client);
}
}

private static void processCommand(PathChildrenCache cache) {
     boolean isDone=false;
     try{
         addListener(cache);
         while(!isDone){
             Thread.sleep(Long.MAX_VALUE);
         }
     }catch (Exception e){

     }finally {

     }

}

private static void addListener(PathChildrenCache cache)
   {
             // a PathChildrenCacheListener is optional. Here, it's used just to log changes
             PathChildrenCacheListener listener = new PathChildrenCacheListener()
             {
                     public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception
                     {
                             switch ( event.getType() )
                             {
                                     case CHILD_ADDED:
                                        {
                                             System.out.println("Node added: " + event.getData().getPath());
                                             break;
                                         }

                                     case CHILD_UPDATED:
                                         {
                                             System.out.println("Node changed: " + event.getData().getPath());
                                             break;
                                         }

                                     case CHILD_REMOVED:
                                         {
                                             System.out.println("Node removed: " + event.getData().getPath());
                                             break;
                                         }
                                 }
                         }
                 };
             cache.getListenable().addListener(listener);
         }
 

}