Zookeeper:Curator增删改查API

2021-03-04 00:26

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标签:for   dia   void   更新   lis   策略   mes   回调   mamicode   

1.介绍

What is Curator?

Curator n ?kyoor??āt?r: a keeper or custodian of a museum or other collection - A ZooKeeper Keeper.

Apache Curator is a Java/JVM client library for Apache ZooKeeper, a distributed coordination service. It includes a highlevel API framework and utilities to make using Apache ZooKeeper much easier and more reliable. It also includes recipes for common use cases and extensions such as service discovery and a Java 8 asynchronous DSL.

curator官网

2.连接对象创建

maven依赖:

    org.apache.zookeeper
            zookeeper
            3.4.10org.apache.curator
            curator-recipes
            2.6.0org.apache.curator
            curator-framework
            2.6.0org.apache.zookeeper
                    zookeeper
                junit
            junit
            4.7test

 连接对象创建的代码

    public static void main(String[] args) {
        CuratorFramework ct = CuratorFrameworkFactory.builder()
                //ip:端口
                .connectString("192.168.10.132:2181,192.168.10.133:2181,192.168.10.135:2181")//连接集群
                //超时时间
                .sessionTimeoutMs(5000)
                //连接断开5秒后,会进行一次重连
                .retryPolicy(new RetryOneTime(5000))
                //命名空间,该命名空间作为父节点
                .namespace("ct").build();
        //打开连接
        ct.start();
        //是否连接成功
        System.out.println(ct.isStarted());
        //关闭连接
        ct.close();
    }

重连策略:

RetryOneTime(int sleepMsBetweenRetry):只重连一次

RetryNTimes(int n, int sleepMsBetweenRetries):重连n次

RetryUntilElapsed(int maxElapsedTimeMs, int sleepMsBetweenRetries):每sleepMsBetweenRetries毫秒重连一次,总等待时间超过maxElapsedTimeMs毫秒后停止重连

ExponentialBackoffRetry(int baseSleepTimeMs, int maxRetries):重连maxRetries次,重连间隔基于baseSleepTimeMs计算
计算公式如下:baseSleepTimeMs*Math.max(1,random.nextInt(1

3.创建节点

        ct.create()
                //节点类型
                .withMode(CreateMode.PERSISTENT)
                //节点权限
                .withACL(ZooDefs.Ids.OPEN_ACL_UNSAFE)
                //节点路径和数据
                .forPath("/node1","node1".getBytes());

 支持递归创建节点

        ct.create()
                //父节点不存在则创建
                .creatingParentsIfNeeded()
                //节点类型
                .withMode(CreateMode.PERSISTENT)
                //节点权限
                .withACL(ZooDefs.Ids.OPEN_ACL_UNSAFE)
                //节点路径和数据
                .forPath("/node2/node2","node2".getBytes());

 异步方式创建(删除、更新、查询省略):

ct.create()
        //父节点不存在则创建
        .creatingParentsIfNeeded()
        //节点类型
        .withMode(CreateMode.PERSISTENT)
        //节点权限
        .withACL(ZooDefs.Ids.OPEN_ACL_UNSAFE)
        //异步回调
        .inBackground(new BackgroundCallback() {
            public void processResult(CuratorFramework client, CuratorEvent event) throws Exception {
                System.out.println(event.getPath()+":"+event.getType());
            }
        })
        //节点路径和数据
        .forPath("node3","node3".getBytes());

4.更新节点 

ct.setData().withVersion(-1).forPath("/node3","node33".getBytes());

5.删除节点

ct.delete().withVersion(-1).forPath("/node3");

 删除包含子节点的节点

//递归删除
ct.delete()
         .deletingChildrenIfNeeded()
         .withVersion(-1).forPath("/node2");

6.查询节点

//查询
byte[] bytes = ct.getData().forPath("/node1");
System.out.println(new String(bytes));

读取属性:

Stat stat = new Stat();
byte[] bytes = ct.getData()
     .storingStatIn(stat).forPath("/node1");
System.out.println(new String(bytes));
System.out.println(stat);

技术图片

7.查询子节点数据 

//  /ct/node1/node2
List list = ct.getChildren().forPath("/node1");
for (String s : list) {
       System.out.println(s);
}

8.判断节点是否存在

//如果节点不存在,则返回值为null
Stat stat = ct.checkExists().forPath("/node11");

  

Zookeeper:Curator增删改查API

标签:for   dia   void   更新   lis   策略   mes   回调   mamicode   

原文地址:https://www.cnblogs.com/wwjj4811/p/12956935.html


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