Common command operations of zookeeper version 3.4.14

Client Shell command operation

Node type:

 

Create node - permanent node

First start the zookeeper client----zkCli.sh -server host name: port number

 

 Create node-temporary node

 Modify node value

 Delete node

 Listen for changes in nodes

Changes in node content:

 Modify the value under /sanguo on another node

 You can see the changes monitored on the hadoop201 node:

 Monitor changes in child nodes of a node--ls Path -w Same way

Java API operations

1 guide package

<!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.4.14</version>
</dependency>

2 Create log4j.properties in main/src/sources

# 全局日志配置
log4j.rootLogger=INFO, stdout
# 控制台输出
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

3 zookeeper java api test

import org.apache.zookeeper.*;
import org.apache.zookeeper.data.ACL;

import java.io.IOException;
import java.util.List;

public class ZooKeeperDemo {
    static ZooKeeper zooKeeper;
    static String connectionString="hadoop200:2181,hadoop201:2181,hadoop202:2181";
    static int time=4000000;
    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {

            //连接zookeeper集群
         zooKeeper = new ZooKeeper(connectionString, time, new Watcher() {
             public void process(WatchedEvent watchedEvent) {

             }

        });


        //查看/目录下的节点
        List<String> children = zooKeeper.getChildren("/", false);
        for (String child : children) {
            System.out.print(child+"\t");

        }
        System.out.println();


        //创建一个新节点
        if(zooKeeper.exists("/china",false)==null)//判断该节点是否事先存在，如果已经存在再创建会报错
        {
          zooKeeper.create("/china", "beijing".getBytes(),ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
        }
        
         //获取节点内容
        byte[] data1 = zooKeeper.getData("/china", false, null);
        System.out.println("/china: "+new String(data1));

        //删除节点
        if(zooKeeper.exists("/CC",false)!=null)
            zooKeeper.delete("/CC",Version.REVISION);
        
        //查看删除后的节点
        List<String> children1 = zooKeeper.getChildren("/", false);
        System.out.println("delete /CC node:");
        for (String child : children1) {
            System.out.print(child+"\t");

        }
        System.out.println();

        //修改节点内容
        zooKeeper.setData("/sanguo","shuguo".getBytes(),-1);

    }
}