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: /example

node path is: /example

event 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: INITIALIZED

node data: null

init child data: child data

event type: CHILD_ADDED

node 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]}