Zookeeper客户端curator常用法

Maven配置

<dependency>    <groupId>org.apache.curator</groupId>    <artifactId>curator-framework</artifactId></dependency><dependency>    <groupId>org.apache.curator</groupId>    <artifactId>curator-recipes</artifactId></dependency>

基本用法

增删查改

public static void main( String[] args ) throws Exception {    //创建重连策略    RetryPolicy retryPolicy = new ExponentialBackoffRetry(1000, 3);    //创建会话    CuratorFramework client = CuratorFrameworkFactory.builder()            .connectString("localhost:2181")            .sessionTimeoutMs(5000)            .retryPolicy(retryPolicy)            .build();    client.start();    String path = "/example";    //创建节点    client.create().creatingParentsIfNeeded().withMode(CreateMode.EPHEMERAL).forPath(path, "init".getBytes());    //读取数据节点    byte[] data = client.getData().forPath(path);    System.out.println("init data is: " + new String(data));    //更新数据节点    client.setData().forPath(path, "update data".getBytes());    //删除数据节点    client.delete().deletingChildrenIfNeeded().forPath(path);}

异步接口

//请参考前面代码...//关键代码final CountDownLatch cdl = new CountDownLatch(1);String path = "/example";//创建节点client.create().creatingParentsIfNeeded().withMode(CreateMode.EPHEMERAL)        //创建成功后回调方法        .inBackground(new BackgroundCallback() {            @Override            public void processResult(CuratorFramework curatorFramework, CuratorEvent curatorEvent) throws Exception {                System.out.println("node name is: " + curatorEvent.getName());                System.out.println("node path is: " + curatorEvent.getPath());                System.out.println("event type: " + curatorEvent.getType());                cdl.countDown();            }        })        .forPath(path, "init".getBytes());System.out.println("already commit!");cdl.await();

输出：

already commit!node name is: /examplenode path is: /exampleevent type: CREATE

事件监听

数据节点监听

public static void watchNode() throws Exception {    client.start();    //创建节点    client.create().creatingParentsIfNeeded().withMode(CreateMode.EPHEMERAL).forPath(path, "init".getBytes());    final NodeCache nodeCache = new NodeCache(client, path);    nodeCache.start();    final CountDownLatch countDownLatch = new CountDownLatch(1);    nodeCache.getListenable().addListener(new NodeCacheListener() {        @Override        public void nodeChanged() throws Exception {            byte[] data = nodeCache.getCurrentData().getData();            System.out.println(new String(data));            countDownLatch.countDown();        }    });    client.setData().forPath(path, "update node".getBytes());    countDownLatch.await();}

输出：

update node

数据子节点监听

public static void watchChildrenNode() throws Exception {    client.start();    //创建节点    final NodeCache nodeCache = new NodeCache(client, path);    nodeCache.start();    final CountDownLatch countDownLatch = new CountDownLatch(2);    PathChildrenCache pathChildrenCache = new PathChildrenCache(client, path, true);    pathChildrenCache.start(PathChildrenCache.StartMode.POST_INITIALIZED_EVENT);    pathChildrenCache.getListenable().addListener(new PathChildrenCacheListener() {        @Override        public void childEvent(CuratorFramework curatorFramework, PathChildrenCacheEvent pathChildrenCacheEvent) throws Exception {            System.out.println("event type: " + pathChildrenCacheEvent.getType());            System.out.println("node data: " + pathChildrenCacheEvent.getData());            countDownLatch.countDown();        }    });    client.create().withMode(CreateMode.EPHEMERAL).forPath(path + "/child", "child data".getBytes());    System.out.println("init child data: " + new String(client.getData().forPath(path + "/child")));    client.setData().forPath(path + "/child", "set child data".getBytes());    countDownLatch.await();}

输出：

event type: INITIALIZEDnode data: nullinit child data: child dataevent type: CHILD_ADDEDnode data: ChildData{path='/example/child', stat=151,151,1453725266116,1453725266116,0,0,0,95263405746815019,10,0,151, data=[99, 104, 105, 108, 100, 32, 100, 97, 116, 97]}