Curator It is an open-source Zookeeper client of Netflix. Compared with the native client provided by Zookeeper, the cursor has a higher level of abstraction and simplifies the programming of Zookeeper client.

Maven dependence

  <dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.4.9</version>
</dependency>


  <dependency>
        <groupId>org.apache.curator</groupId>
        <artifactId>curator-recipes</artifactId>
        <version>2.7.0</version>
    </dependency>

1. Create a cursor connection instance (2 ways)

CuratorFramework client = CuratorFrameworkFactory.newClient(address, new ExponentialBackoffRetry(1000, 3));

CuratorFramework client = CuratorFrameworkFactory.builder()
                .connectString(address)
                .sessionTimeoutMs(1000)
                .retryPolicy(retryPolicy)
                .build();

The CuratorFramework must be called before it can be used

client.start();

After a series of operations, call client.close(); method, and try finally statement can be used:

CuratorFramework client = CuratorFrameworkFactory.newClient(address, new ExponentialBackoffRetry(1000, 3));
try{
    client.start();
    ...
}finally {
    if(client!=null)
        client.close();
}

2. Create node

A. create a permanent node

client.create()
      .creatingParentContainersIfNeeded()
      .withMode(CreateMode.PERSISTENT)
      .withACL(ZooDefs.Ids.OPEN_ACL_UNSAFE)
      .forPath(path, "hello, zk".getBytes());

b. create a temporary node

client.create().withMode(CreateMode.EPHEMERAL).forPath(path, "hello".getBytes());

3. Get node value

byte[] buf = client.getData().forPath(path);System.out.println("get data path:"+path+", data:"+new String(buf));

4. Set node value

client.setData().inBackground().forPath(path, "ricky".getBytes());

5.checkExists

Stat stat = client.checkExists().forPath(path);
if(stat==null){
    System.out.println("exec create path:"+path);
}else {
    System.out.println("exec getData");
}

6. Delete node

client.delete().deletingChildrenIfNeeded().forPath("/pandora");