【6】Zookeeper脚本及API

一、客户端脚本

1.1、客户端连接

cd /usr/local/services/zookeeper/zookeeper-3.4.13/bin
##连接本地Zookeeper服务器
sh zkCli.sh
##连接主机server1上的zookeeper服务
sh zkCli.sh -server server1:2181

1.2、CRUD操作

创建

##语法：create [-s] [-e] path data acl
create /zk-temp "tmp"

说明：-s / -e分别制定节点特性：顺序或临时节点。默认情况下，创建的是持久节点。

读取

##获取节点子节点列表，语法：ls path [watch]
ls /zk-temp
##获取节点数据，语法：get path [watch]
get /zk-temp

更新

##语法：set path data [version]
set /zk-temp "zk"

删除

##语法：delete path [version]
delete /zk-temp

二、Java客户端API

2.1、创建会话

创建会话Java代码

  
package zookeeper.javaapi;
import java.util.concurrent.CountDownLatch;

import org.apache.zookeeper.WatchedEvent;

import org.apache.zookeeper.Watcher;

import org.apache.zookeeper.ZooKeeper;
public class CreateSession implements Watcher {
private static CountDownLatch connectedSemaphore = new CountDownLatch(1);

public void process(WatchedEvent event) {
    System.out.println("Receive watched event：" + event);
    if (Event.KeeperState.SyncConnected == event.getState()) {
        connectedSemaphore.countDown();
    }
}

public static void main(String[] args) throws Exception{	
    ZooKeeper zooKeeper = new ZooKeeper("server1:2181",1000,new CreateSession());
    System.out.println(zooKeeper.getState());
    try {
    	connectedSemaphore.await();        	
    } catch(InterruptedException e) {
    	e.printStackTrace();
    }
    System.out.println("Zookeeper session established.");
}

}


2.2、创建节点

2.2.1、同步创建节点

方法：String create(final String path, byte data[], List acl, CreateMode createMode)
参数说明：

同步创建节点Java代码

  
package zookeeper.javaapi;
import java.util.concurrent.CountDownLatch;

import org.apache.zookeeper.CreateMode;

import org.apache.zookeeper.WatchedEvent;

import org.apache.zookeeper.Watcher;

import org.apache.zookeeper.Watcher.Event.KeeperState;

import org.apache.zookeeper.ZooDefs.Ids;

import org.apache.zookeeper.ZooKeeper;
/**


ZooKeeper API创建节点，使用同步(sync)接口。

*/

public class Sync_Create_Usage implements Watcher {
private static CountDownLatch connectedSemaphore = new CountDownLatch(1);
public static void main(String[] args) throws Exception{
 ZooKeeper zookeeper = new ZooKeeper("server1:2181", 5000, new Sync_Create_Usage());
 connectedSemaphore.await();
         
 //创建临时节点
 String path1 = zookeeper.create("/zk-test-ephemeral-", "".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
 System.out.println("Success create znode: " + path1);

 //临时顺序节点
 String path2 = zookeeper.create("/zk-test-ephemeral-", "".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
 System.out.println("Success create znode: " + path2);
 
 //阻塞线程，查看临时节点创建结果
 Thread.sleep( Integer.MAX_VALUE );

}

public void process(WatchedEvent event) {

if (KeeperState.SyncConnected == event.getState()) {

connectedSemaphore.countDown();

}

}

}