ZooKeeper集群API操作

1.添加依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>HadoopDemo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-common</artifactId>
            <version>3.3.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-hdfs</artifactId>
            <version>3.3.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>3.3.1</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.4.8</version>
            <type>pom</type>
        </dependency>
    </dependencies>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

</project>

2.新建包org.zookeeper,类ZooKeeperDemo

package org.zookeeper;

import org.apache.zookeeper.*;
import org.apache.zookeeper.data.Stat;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.concurrent.CountDownLatch;

public class ZooKeeperDemo {

    public  void main(String[] args) throws IOException, InterruptedException {
        getConnect();
    }
    ZooKeeper zooKeeper=null;
    CountDownLatch cdl=null;
    //连接Zookeeper server
    @Before
    public  void getConnect() throws IOException, InterruptedException {
        String zkServer = "192.168.157.142:2181";//ip:port
        cdl = new CountDownLatch(1);
        zooKeeper = new ZooKeeper(zkServer, 3000, new Watcher() {
            @Override
            public void process(WatchedEvent watchedEvent) {
                System.out.println("通知状态:"+watchedEvent.getState()+" "+"事件类型:"+
                        watchedEvent.getType()+"节点路径:"+watchedEvent.getPath());
                if(watchedEvent.getState()==Event.KeeperState.SyncConnected){
                    cdl.countDown();
                }

            }
        });
        cdl.await();
    }

    //创建节点
    @Test
    public void createNode() throws InterruptedException, KeeperException {
        zooKeeper.create("/lxz","20203001".getBytes(),
                ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
        zooKeeper.create("/lxz/child","20203001".getBytes(),
                ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
    }
    //判断节点是否存在
    @Test
    public void isExist() throws InterruptedException, KeeperException {
        Stat s=zooKeeper.exists("/lxz",true);
        if(s!=null) {
            System.out.println("已存在");
        }else{
            System.out.println("不存在");
        }
    }
    //获取节点的数据
    @Test
    public void getNode() throws InterruptedException, KeeperException {
        byte[] data=zooKeeper.getData("/lxz",true,null);
        System.out.println("节点/lxz的数据内容为："+new String(data));
    }
    @Test
    public void updateNode() throws InterruptedException, KeeperException {
        Stat s =zooKeeper.exists("/lxz",true);
        System.out.println("创建时间："+s.getCtime());
        System.out.println("版本号"+s.getCversion());
        System.out.println("数据长度"+s.getDataLength());
        System.out.println("子节点个数"+s.getNumChildren());

        zooKeeper.setData("/lxz","wq 2301302827".getBytes(),-1);
        byte[] data=zooKeeper.getData("/lxz",true,null);
        System.out.println("节点、lxz的节点数据更新为"+new String(data));

         s =zooKeeper.exists("/lxz",true);
        System.out.println("创建时间："+s.getCtime());
        System.out.println("版本号"+s.getCversion());
        System.out.println("数据长度"+s.getDataLength());
        System.out.println("子节点个数"+s.getNumChildren());

    }
    @Test
    public void getChildren() throws InterruptedException,KeeperException {
        List<String> nodelist =zooKeeper.getChildren("/lxz",false);
        for(String node:nodelist){
            System.out.println("/lxz节点的子节点有："+node);
        }
    }
    //删除子节点
    @Test
    public void deleteNode() throws InterruptedException, KeeperException {
        zooKeeper.delete("/lxz/a",-1);
        zooKeeper.delete("/lxz/b",-1);
        zooKeeper.delete("/lxz/c",-1);
        zooKeeper.delete("/lxz/child",-1);
        zooKeeper.delete("/lxz",-1);

    }
}