ZookeeperAPI

package com;

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

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

public class ZkClient {

    private ZooKeeper zookeeper;

    /**
     * 创建新节点 create
     * @throws IOException
     */
    @Test
    public void create() throws IOException, KeeperException, InterruptedException {
        //2.创建新节点
        zookeeper.create(
                "/testAPI2", //创建节点的路径名
                "1234".getBytes(), //存入Zookeeper的数据
                ZooDefs.Ids.OPEN_ACL_UNSAFE,//访问控制列表（权限）
                CreateMode.PERSISTENT);//节点类型
    }
    @Before
    public void before() throws IOException {
        //zookeeper连接地址
        String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181,";
        //会话响应超时时间
        int sessionTimeout = 2000;
        //1.创建一个Zookeeper对象
       zookeeper = new ZooKeeper(connectString, //Zookeeper地址
                sessionTimeout,//超时时间
                new Watcher() {
                    //Zookeeper监听的回调函数
                    public void process(WatchedEvent watchedEvent) {
                    }
                });
    }
    @After
    public void After() throws InterruptedException {
        //3.关闭资源
        zookeeper.close();
    }

    /**
      查询 ls
    */
    @Test
    public void ls() throws KeeperException, InterruptedException {
        List<String> ls = zookeeper.getChildren("/", new Watcher() {
            public void process(WatchedEvent watchedEvent) {
                System.out.println("自定义回调函数");
            }
        });
        for (String l : ls) {
            System.out.println(l);
        }
        //开启监听的情况下，开启线程阻塞，否则守护线程挂掉，无法继续监听
        Thread.sleep(Long.MAX_VALUE);
    }

    /**
      查询节点的值 get
    */
    @Test
    public void get() throws KeeperException, InterruptedException, IOException {

        //-s  附加次级信息(节点状态)stat结构体
        Stat stat = new Stat();
        byte[] data = zookeeper.getData("/testAPI", false, stat);
        
        System.out.println(stat.getDataLength());
        System.out.write(data);
        System.out.println();

    }
    
    /**
      查询节点状态 stat
    */
    @Test
    public void stat() throws KeeperException, InterruptedException {
        Stat stat = zookeeper.exists("/testAPI", false);
        if (stat == null){
            System.out.println("节点不存在");
        }else {
            System.out.println(stat);
        }
    }
    /**
      修改节点 set
    */
    @Test
    public void set() throws KeeperException, InterruptedException {
        String node = "/testAPI";
        //确认节点状态
        Stat stat = zookeeper.exists(node, false);
        //乐观锁
        if (stat==null){
            System.out.println("节点不存在");
        }else {
            zookeeper.setData("/testAPI","456".getBytes(),stat.getVersion());
        }
    }
    /**
      删除节点
    */
    @Test
    public void delete() throws KeeperException, InterruptedException {
        String node = "/testAPI";
        //确认节点状态
        Stat stat = zookeeper.exists(node, false);
        //乐观锁 version目的是保证，我要修改的和我实际修改的目标是一致的
        if (stat==null){
            System.out.println("节点不存在");
        }else {
            zookeeper.delete("/testAPI",stat.getVersion());
        }
    }
}

log4j.properties

log4j.rootLogger=INFO, stdout  
log4j.appender.stdout=org.apache.log4j.ConsoleAppender  
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout  
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n  
log4j.appender.logfile=org.apache.log4j.FileAppender  
log4j.appender.logfile.File=target/spring.log  
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout  
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n  

pom.xml

<?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>zookeeper</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.8.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.5.7</version>
        </dependency>
    </dependencies>

</project>