[大数据] zookeeper JAVA API 使用

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/u014679456/article/details/81240259

---

title: [大数据] zookeeper JAVA API 使用
tags:
- zookeeper
- 大数据
- 分布式
categories:
- 大数据
date: 2017-07-10 18:57:38
description: [大数据] zookeeper JAVA API 使用

---

1.基本使用

org.apache.zookeeper.Zookeeper是客户端入口主类，负责建立与server的会话
它提供了表 1 所示几类主要方法 ：

功能	描述
create	在本地目录树中创建一个节点
delete	删除一个节点
exists	测试本地是否存在目标节点
get/set data	从目标节点上读取?/?写数据
get/set ACL	获取?/?设置目标节点访问控制列表信息
get children	检索一个子节点上的列表
sync	等待要被传送的数据

表 1 ： ZooKeeper API 描述

2.demo增删改查

package bigdata03.zk;


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

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

/**
 * Created by 57871 on 2018/6/20.
 */
public class SimpleZK {

    private  static  final String connectString = "bigdata01.com:2181,bigdata02.com:2181,bigdata03.com:2181";
    private  static  final int sessionTimeout = 2000;
    ZooKeeper zkClient = null;


    @Before
    public void init() throws IOException {

        zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {

            @Override
            public void process(WatchedEvent event) {
                //接受到监听事件的处理步骤
                System.out.println(event.getType() + "--->"+event.getPath());

                try {
                    List<String> children = zkClient.getChildren("/",true);

                    for(String child : children){
                        System.out.println( child );
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }

            }
        });

    }

    /**
     *数据添加
     * @throws Exception
     */
    @Test
    public  void testCreate() throws Exception {

        //参数1 路径  para2 内容  para3 权限   param4
        zkClient.create("/idea","hello zk".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    }

    /**
     * 判断是否存在Znode
     * @throws KeeperException
     * @throws InterruptedException
     */
    @Test
    public  void  isExist() throws KeeperException, InterruptedException {
        Stat stat = zkClient.exists("/idea", false);
        System.out.println(stat != null ? "exist" : "not exist");
    }

    /**
     * 判断Znode下的子节点
     * @throws KeeperException
     * @throws InterruptedException
     */
    @Test
    public void  getChildren() throws KeeperException, InterruptedException {
        List<String> children = zkClient.getChildren("/",true);
        for(String child : children){
            System.out.println( child );
        }
    }

    /**
     * 获得Znode的数据信息
     * @throws KeeperException
     * @throws InterruptedException
     * @throws UnsupportedEncodingException
     */
    @Test
    public  void getData() throws KeeperException, InterruptedException, UnsupportedEncodingException {
        byte[] data = zkClient.getData("/idea", false, null);
        System.out.println(new String(data,"utf-8"));
    }

    /**
     * 修改Znode的数据信息
     * @throws KeeperException
     * @throws InterruptedException
     */
    @Test
    public void setData() throws KeeperException, InterruptedException {
        Stat stat = zkClient.setData("/idea", "hellowordzk2".getBytes(), -1);
    }

    @Test
    public void deleteData() throws KeeperException, InterruptedException {
        zkClient.delete("/idea",-1);
    }

}