zookeeper开发

环境
　　虚拟机：VMware 10
　　Linux版本：CentOS-6.5-x86_64
　　客户端：Xshell4
　　FTP：Xftp4
　　jdk8
　　zookeeper-3.4.11

ZK客户端操作命令：

#登录ZK客户端
[root@PCS102 bin]# ./zkCli.sh
Connecting to localhost:2181
Welcome to ZooKeeper!
JLine support is enabled

WATCHER::

WatchedEvent state:SyncConnected type:None path:null
[zk: localhost:2181(CONNECTED) 0]

#查看客户端有哪些命令：
[zk: localhost:2181(CONNECTED) 0] help
ZooKeeper -server host:port cmd args
    stat path [watch]
    set path data [version]
    ls path [watch]
    delquota [-n|-b] path
    ls2 path [watch]
    setAcl path acl
    setquota -n|-b val path
    history 
    redo cmdno
    printwatches on|off
    delete path [version]
    sync path
    listquota path
    rmr path
    get path [watch]
    create [-s] [-e] path data acl
    addauth scheme auth
    quit 
    getAcl path
    close 
    connect host:port
#创建节点
[zk: localhost:2181(CONNECTED) 1] create /wjy hello
Created /wjy
#列出根目录下所有节点
[zk: localhost:2181(CONNECTED) 2] ls /
[wjy,zookeeper]
#获取/wjy节点的值
[zk: localhost:2181(CONNECTED) 3] get /wjy 
hello
cZxid = 0x411320000000d
ctime = Mon Mar 04 16:25:22 CST 2019
mZxid = 0x411320000000d
mtime = Mon Mar 04 16:25:22 CST 2019
pZxid = 0x411320000000d
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 5
numChildren = 0
#更新/wjy节点的值
[zk: localhost:2181(CONNECTED) 4] set /wjy nihao
cZxid = 0x411320000000d
ctime = Mon Mar 04 16:25:22 CST 2019
mZxid = 0x411320000000e
mtime = Mon Mar 04 16:25:55 CST 2019
pZxid = 0x411320000000d
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 5
numChildren = 0
[zk: localhost:2181(CONNECTED) 13] 

分别代表的时间戳对应为：
cZxid
    对应为该节点的创建时间（Create）

mZxid
    对应该节点的最近一次修改的时间（Mofify）
    与其子节点无关

pZxid
    这个节点就和子节点有关啦！
    是与 该节点的子节点（或该节点）的最近一次 创建 / 删除 的时间戳对应
    注：只与 本节点 / 该节点的子节点，有关；与孙子节点无关。

java操作示例：

package testZK;

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

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZookeeperTest {
    
    /**session过期时间*/
    private static final int SESSION_TIMEOUT = 30000;
    
    public static final Logger LOGGER = LoggerFactory.getLogger(ZookeeperTest.class);
    
    /**定义监听类*/
    private Watcher watcher =  new Watcher() {

        public void process(WatchedEvent event) {
            LOGGER.info("process : " + event.getType());
        }
    };
    
    private ZooKeeper zooKeeper;
    
    /**
     * 连接ZK集群并启用监听对象watcher
     * @throws IOException
     */
    @Before
    public void connect() throws IOException {
//        indicate : all servers 
        zooKeeper  = new ZooKeeper("192.168.133.19:2181,192.168.133.20:2181,192.168.133.21:2181", 
        SESSION_TIMEOUT, 
        watcher);
    }
    
    /**
     *  关闭
     */
    @After
    public void close() {
        try {
            zooKeeper.close();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    /**
     * 创建 znode 
     *  1.CreateMode  
     *  PERSISTENT
     *  PERSISTENT_SEQUENTIAL  序列化的持久节点
     *  EPHEMERAL  临时节点  session过期 就会消失
     *  EPHEMERAL_SEQUENTIAL   序列化的临时节点
     *  Access Control List: 访问控制列表
     *  https://baike.baidu.com/item/ACL/362453?fr=aladdin
     *  OPEN_ACL_UNSAFE: ANYONE CAN VISIT 
     * <br>------------------------------<br>
     */
    @Test
    public void testCreate() {
        String result = null;
         try {
             result = zooKeeper.create("/zk002", //路径
             "zk002data-e".getBytes(), //赋值 注意放的是字节
             Ids.OPEN_ACL_UNSAFE,      //访问的安全模式
             CreateMode.EPHEMERAL);    //节点类型 PERSISTENT  持久化节点    EPHEMERAL 临时的节点
             
             Thread.sleep(30000);
        } catch (Exception e) {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
        LOGGER.info("create result : {}", result);
     }
    
    /**
     * 删除
     */
    @Test
    public void testDelete() {
        try 
        {
            zooKeeper.delete("/zk001", -1);
        }
        catch (Exception e) 
        {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
    }
    
    /**
     *  获取值
     */
    @Test
    public void testGetData() {
        String result = null;
        try 
        {
             byte[] bytes = zooKeeper.getData("/sxt", null, null);
             result = new String(bytes);
        } 
        catch (Exception e) 
        {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
        LOGGER.info("getdata result--------- : {}", result);
    }
    
    @Test
    public void testGetData01() throws Exception {
        String result = null;
        try {
            byte[] bytes = zooKeeper.getData("/zk001", null, null);
            result = new String(bytes);
        } catch (Exception e) {
            LOGGER.error(e.getMessage());
            Assert.fail();
        }
        LOGGER.info("getdata result--1------ : {}", result);
        
        Thread.sleep(30000);
        
        byte[] bytes;
        try 
        {
            bytes = zooKeeper.getData("/zk001", null, null);
            result = new String(bytes);
        } catch (KeeperException | InterruptedException e) {
            e.printStackTrace();
        }
        LOGGER.info("getdata result--2----- : {}", result);
                
    }
    
    /**
     *   注册监听事件
     */
    @Test
    public void testGetDataWatch() {
        String result = null;
         try {
             System.out.println("get:");
             byte[] bytes = zooKeeper.getData("/zk001", new Watcher() {
                public void process(WatchedEvent event) {
                    LOGGER.info("testGetDataWatch  watch : {}", event.getType());
                    System.out.println("watcher ok");
                }
             }, null);
             result = new String(bytes);
        } catch (Exception e) {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
         LOGGER.info("getdata result------------------------------------------ : {}", result);
         
         // Watcher会单独起一个线程来处理  仅注册监听1次
         try {
             System.out.println("set1:");
             zooKeeper.setData("/zk001", "testSetDataWAWWW".getBytes(), -1);
             System.out.println("set2:");
             zooKeeper.setData("/zk001", "testSetDataWAWWW".getBytes(), -1);
        } catch (Exception e) {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
         System.out.println("over");
    }
    
    /**
     * 判断是否存在某个节点
     */
    @Test
    public void testExists() {
        Stat stat = null;
        try{
            stat = zooKeeper.exists("/zk001", false);
        } catch (Exception e) {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
        Assert.assertNotNull(stat);
        LOGGER.info("exists result : {}", stat.getCzxid());
    }
    
    /**
     * 赋值
     */
    @Test
    public void testSetData() {
        Stat stat = null;
         try {
             stat = zooKeeper.setData("/zk001", "testSetData".getBytes(), -1);
        } catch (Exception e) {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
         Assert.assertNotNull(stat);
         LOGGER.info("exists result : {}", stat.getVersion());    
    }
    
    /**
     * 
     */
    @Test
    public void testExistsWatch1() {
        Stat stat = null;
         try {
             stat = zooKeeper.exists("/zk001", true);
        } catch (Exception e) {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
         Assert.assertNotNull(stat);
         
         try {
            zooKeeper.delete("/zk001", -1);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    /**
     *   校验节点是否存在
     */
    @Test
    public void testExistsWatch2() {
        Stat stat = null;
         try {
             stat = zooKeeper.exists("/zk002", new Watcher() {
                @Override
                public void process(WatchedEvent event) {
                    LOGGER.info("testExistsWatch2  watch : {}", event.getType());
                }
             });
        } catch (Exception e) {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
         Assert.assertNotNull(stat);
         
         // 赋值
         try {
            zooKeeper.setData("/zk002", "testExistsWatch2".getBytes(), -1);
        } catch (Exception e) {
            e.printStackTrace();
        }
         
         // 删除
         try {
            zooKeeper.delete("/zk002", -1);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    /**
     *  获取子节点
     */
    @Test
    public void testGetChild() {
         try {
             zooKeeper.create("/zk/001", "001".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
             zooKeeper.create("/zk/002", "002".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
             
             List<String> list = zooKeeper.getChildren("/zk", true);
            for (String node : list) {
                LOGGER.info("fffffff {}", node);
            }
        } catch (Exception e) {
             LOGGER.error(e.getMessage());
             Assert.fail();
        }
    }
}

代码连接：

https://download.csdn.net/download/cac2020/11002142