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Java原生API操作Zookeeper(二)


基于Curator操作ZooKeeper可参看:

​​基于Curator操作ZooKeeper(一)-基本操作​​

​​基于Curator操作ZooKeeper(二)-Watcher操作​​

​​基于Curator操作ZooKeeper(二)-Watcher操作-补充TreeCache​​

相关内容:

​​Java原生API操作Zookeeper(一)​​

操作一

建立、关闭连接,查看状态:

Java原生API操作Zookeeper(二)_java

Java原生API操作Zookeeper(二)_zookeeper_02

ZK的客户端和服务端的连接有这么几种主要的状态:

Java原生API操作Zookeeper(二)_System_03

NOT_CONNECTED:尚未连接

CONNECTING:连接中

CONNECTED:已连接

CLOSED:关闭

操作二

增加Watcher:

Java原生API操作Zookeeper(二)_System_04

Java原生API操作Zookeeper(二)_java_05

操作三

CRUD:

Stat类包含了节点的属性:

Java原生API操作Zookeeper(二)_System_06

Java原生API操作Zookeeper(二)_System_07

package com.zj.bda.web.zookeeper;

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

import java.io.IOException;
import java.util.concurrent.CountDownLatch;

/**
* @author Dongguabai
* @date 2018/10/8 15:20
*/
public class JavaZookeeper1 {

static final String CONNECT_ADDR = "192.168.220.135:2181,192.168.220.136:2181,192.168.220.137:2181";
static final int SESSION_OUTTIME = 2000;//ms
/** 阻塞程序执行,等待zookeeper连接成功*/
static final CountDownLatch connectedSemaphore = new CountDownLatch(1);

static final String PATH = "/dongguabai";
public static void main(String[] args) {
try {
//连接
ZooKeeper zk = new ZooKeeper(CONNECT_ADDR, SESSION_OUTTIME, event->{
//如果收到了服务端的响应事件,连接成功
if (Watcher.Event.KeeperState.SyncConnected==event.getState()){
connectedSemaphore.countDown();
}
});
connectedSemaphore.await();
System.out.println("连接成功!");
//获取状态
System.out.println(zk.getState());
//创建节点
//节点路径,节点内容,权限,节点类型
zk.create(PATH, "0".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);

Stat stat = new Stat();

//获取节点
byte[] res = zk.getData(PATH, null, stat);
String re = new String(res);
System.out.println("获取节点内容为:"+re);

//修改节点
//节点路径,节点内容,version:相当于乐观锁的概念,这里保证当前修改的version是正确的
zk.setData(PATH,"1".getBytes(),stat.getVersion());
//获取节点
byte[] res2 = zk.getData(PATH, null, stat);
String re2 = new String(res2);
System.out.println("修改之后,获取节点内容为:"+re2);

//删除节点
zk.delete(PATH,stat.getVersion());
//获取节点
byte[] res3 = zk.getData(PATH, null, stat);
String re3 = new String(res3);
System.out.println("删除之后,获取节点内容为:"+re3);

//关闭连接
zk.close();
} catch (IOException | InterruptedException | KeeperException e) {
e.printStackTrace();
}
}
}

输出内容:

Java原生API操作Zookeeper(二)_java_08


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