Zookeeper实例原生API--异步创建节点

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import java.util.concurrent.CountDownLatch;import org.apache.zookeeper.AsyncCallback;import org.apache.zookeeper.CreateMode;import org.apache.zookeeper.WatchedEvent;import org.apache.zookeeper.Watcher;import org.apache.zookeeper.Watcher.Event.KeeperState;import org.apache.zookeeper.ZooDefs.Ids;import org.apache.zookeeper.ZooKeeper;/** * * @ClassName: ZooKeeper_Create_API_ASync_Usage * @Description: TODO(ZooKeeper API创建节点，使用异步(async)接口。) * @author RongShu* @date 2017年6月11日 下午8:29:44 * */public class ZooKeeper_Create_API_ASync_Usage implements Watcher {    private static CountDownLatch connectedSemaphore = new CountDownLatch(1);    public static void main(String[] args) throws Exception{ ZooKeeper zookeeper = new ZooKeeper("localhost:2181",5000,new ZooKeeper_Create_API_ASync_Usage()); connectedSemaphore.await(); zookeeper.create("/zk-test-ephemeral-", "".getBytes(),Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL, new IStringCallback(), "I am context."); zookeeper.create("/zk-test-ephemeral-", "".getBytes(),Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL,new IStringCallback(), "I am context."); zookeeper.create("/zk-test-ephemeral-", "".getBytes(),Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL,new IStringCallback(), "I am context."); Thread.sleep( Integer.MAX_VALUE );    }    public void process(WatchedEvent event) {        if (KeeperState.SyncConnected == event.getState()) {            connectedSemaphore.countDown();        }    }}class IStringCallback implements AsyncCallback.StringCallback{  public void processResult(int rc, String path, Object ctx, String name) {    System.out.println("Create path result: [" + rc + ", " + path + ", " + ctx + ", real path name: " + name);    }  }输出Create path result: [0, /zk-test-ephemeral-, I am context., real path name: /zk-test-ephemeral-Create path result: [-110, /zk-test-ephemeral-, I am context., real path name: nullCreate path result: [0, /zk-test-ephemeral-, I am context., real path name: /zk-test-ephemeral-0000000021

注意:

AsyncCallback包含了StatCallback、DataCallback、ACLCallback、ChildrenCallback、Children2Callback、StringCallback和VoidCallback 七种不同回调接口。和同步接口最大的区别就是：节点创建过程（包括网络通信和服务端的节点创建过程）是异步的，并且在同步接口调用过程中，我们需要关注接口抛出的异常，但是在异步接口中，接口本身不会抛出异常的，所有的异常都会在回调函数中通过Result Code 来体现。

扩展

关于API内容请参看官网或Zookeeper实例原生API--同步创建节点

参考

1.《从Paxos到Zookeeper：分布式一致性原理与实践》

2. https://zookeeper.apache.org/doc/r3.5.3-beta/api/index.html

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