ZooKeeper之java客户端访问-入门介绍

Dear 丶 2022-08-26 01:20 109阅读 0赞

上篇简单的介绍了单点部署ZooKeeper及节点管理。

这里介绍下如何通过java客户端进行各个节点的管理。

具体就不一一介绍，相信从代码的注释中就可以看明白

首先创建一个zookeeper的基础类，里面包含了基本的节点管理方法，如下：

package com.zktest.newtest;
    
    import java.io.IOException;
    import java.util.List;
    import java.util.concurrent.CountDownLatch;
    
    import org.apache.zookeeper.CreateMode;
    import org.apache.zookeeper.KeeperException;
    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;
    import org.apache.zookeeper.data.Stat;
    
    public class BaseZookeeper implements Watcher
    {
    
    	public ZooKeeper zooKeeper;
    
    	private static final int SESSION_TIME_OUT = 2000;
    
    	private CountDownLatch countDownLatch = new CountDownLatch(1);
    
    	/**
    	 * 连接zookeeper
    	 * 
    	 * @param host
    	 * @throws IOException
    	 * @throws InterruptedException
    	 */
    	public void connectZookeeper(String host) throws IOException,
    			InterruptedException
    	{
    		zooKeeper = new ZooKeeper(host, SESSION_TIME_OUT, this);
    		countDownLatch.await();
    		System.out.println("zookeeper connect ok");
    
    	}
    
    	/**
    	 * 实现watcher的接口方法，当连接zookeeper成功后，zookeeper会通过此方法通知watcher<br>
    	 * 此处为如果接受到连接成功的event，则countDown，让当前线程继续其他事情。
    	 */
    	@Override
    	public void process(WatchedEvent event)
    	{
    		if (event.getState() == KeeperState.SyncConnected)
    		{
    			System.out.println("watcher received event");
    			countDownLatch.countDown();
    		}
    	}
    
    	/**
    	 * 根据路径创建节点，并且设置节点数据
    	 * @param path
    	 * @param data
    	 * @return
    	 * @throws KeeperException
    	 * @throws InterruptedException
    	 */
    	public String createNode(String path, byte[] data) throws KeeperException,
    			InterruptedException
    	{
    		return this.zooKeeper.create(path, data, Ids.OPEN_ACL_UNSAFE,
    				CreateMode.PERSISTENT);
    	}
    
    	/**
    	 * 根据路径获取所有孩子节点
    	 * 
    	 * @param path
    	 * @return
    	 * @throws KeeperException
    	 * @throws InterruptedException
    	 */
    	public List<String> getChildren(String path) throws KeeperException,
    			InterruptedException
    	{
    		return this.zooKeeper.getChildren(path, false);
    	}
    
    	public Stat setData(String path, byte [] data, int version) throws KeeperException, InterruptedException
    	{
    		return this.zooKeeper.setData(path, data, version);
    	}
    	
    	/**
    	 * 根据路径获取节点数据
    	 * 
    	 * @param path
    	 * @return
    	 * @throws KeeperException
    	 * @throws InterruptedException
    	 */
    	public byte[] getData(String path) throws KeeperException,
    			InterruptedException
    	{
    		return this.zooKeeper.getData(path, false, null);
    	}
    
    	/**
    	 * 删除节点
    	 * 
    	 * @param path
    	 * @param version
    	 * @throws InterruptedException
    	 * @throws KeeperException
    	 */
    	public void deletNode(String path, int version)
    			throws InterruptedException, KeeperException
    	{
    		this.zooKeeper.delete(path, version);
    	}
    
    	/**
    	 * 关闭zookeeper连接
    	 * 
    	 * @throws InterruptedException
    	 */
    	public void closeConnect() throws InterruptedException
    	{
    		if (null != zooKeeper)
    		{
    			zooKeeper.close();
    		}
    	}
    
    }

创建客户端进行测试，代码如下：

package com.spg.zktest.newtest;
    
    import java.io.IOException;
    import java.util.Arrays;
    import java.util.List;
    
    import org.apache.zookeeper.KeeperException;
    
    public class Client
    {
    
    	/**
    	 * @param args
    	 * @throws InterruptedException 
    	 * @throws IOException 
    	 * @throws KeeperException 
    	 */
    	public static void main(String[] args) throws IOException, InterruptedException, KeeperException
    	{
    		BaseZookeeper baseZookeeper = new BaseZookeeper();
    		
    		String host = "192.168.183.128:2181";
    		
    		// 连接zookeeper
    		baseZookeeper.connectZookeeper(host);
    		System.out.println("--------connect zookeeper ok-----------");
    		
    		// 创建节点
    		byte [] data = {1, 2, 3, 4, 5};
    		String result = baseZookeeper.createNode("/test", data);
    		System.out.println(result);
    		System.out.println("--------create node ok-----------");
    		
    		// 获取某路径下所有节点
    		List<String> children = baseZookeeper.getChildren("/");
    		for (String child : children)
    		{
    			System.out.println(child);
    		}
    		System.out.println("--------get children ok-----------");
    		
    		// 获取节点数据
    		byte [] nodeData = baseZookeeper.getData("/test");
    		System.out.println(Arrays.toString(nodeData));
    		System.out.println("--------get node data ok-----------");
    		
    		// 更新节点数据
    		data = "test data".getBytes();
    		baseZookeeper.setData("/test", data, 0);
    		System.out.println("--------set node data ok-----------");
    		
    		nodeData = baseZookeeper.getData("/test");
    		System.out.println(Arrays.toString(nodeData));
    		System.out.println("--------get node new data ok-----------");
    		
    		baseZookeeper.closeConnect();
    		System.out.println("--------close zookeeper ok-----------");
    	}
    
    }

从命令行中看操作后的结果，如下：

> 1：根目录下节点
> 
> ![Center][]  
> 
> 
> 2：查看test节点信息
> 
> ![20140322224128656][]  
>

OK，测试结果到此结束。

[Center]: /images/20220824/2b8d3805a037419eab9c55b83940adfa.png
[20140322224128656]: /images/20220824/1c76c3f736704a4086b01fd0f3c4962b.png