基于zkdash下Zookeeper完成CRUD及监听

Dear 丶 2021-09-15 00:10 310阅读 0赞

本文主要介绍在zkdash下实现zookeeper的CRUD及监听。

一、环境准备

（1）完全分布式环境，搭建过程可以参考我的另外一篇博客

[《Hadoop完全分布式的搭建》][Hadoop]

（2）安装Zookeeper，安装过程可以参考我的另外一篇博客

[《完全分布式下安装Zookeeper》][Zookeeper]

（3）安装MySQL，安装过程可以参考我的另外一篇博客

[《Linux下安装MySQL》][Linux_MySQL]

（4）安装zkdash，安装过程可以参考我的另外一篇博客

[《Hadoop环境下安装zkdash》][Hadoop_zkdash]

二、启动Zookeeper，查看各个节点的状态

![70][]

![70 1][]

![70 2][]

三、编写代码实现CRUD及监听

pom.xml文件：

<dependency>
          <groupId>org.apache.curator</groupId>
          <artifactId>curator-recipes</artifactId>
          <version>2.12.0</version>
    	</dependency>
    	
    	  
    	<dependency>
          <groupId>org.apache.curator</groupId>
          <artifactId>curator-framework</artifactId>
          <version>2.12.0</version>
    	</dependency>

测试代码：

package com.xzw.zookeeper;
    
    import java.util.List;
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    
    import org.apache.curator.RetryPolicy;
    import org.apache.curator.framework.CuratorFramework;
    import org.apache.curator.framework.CuratorFrameworkFactory;
    import org.apache.curator.framework.recipes.cache.ChildData;
    import org.apache.curator.framework.recipes.cache.PathChildrenCache;
    import org.apache.curator.framework.recipes.cache.PathChildrenCache.StartMode;
    import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
    import org.apache.curator.framework.recipes.cache.PathChildrenCacheListener;
    import org.apache.curator.retry.ExponentialBackoffRetry;
    import org.apache.zookeeper.CreateMode;
    import org.apache.zookeeper.data.Stat;
    /**
     * 
     * @author xzw
     *
     */
    public class ZooCurator {
    	private static String connectString = "192.168.100.68:2181,192.168.100.78:2181,192.168.100.88:2181/testZk";
    	private static CuratorFramework client;
    	private static String rootPath = "/";
    	private static String tmpPath = "/zkTmpAdd";
    	private static String ghPath = "zkAddByCurator";
    	
    	/**
    	 * 创建一个Zookeeper连接
    	 * @return
    	 */
    	private static CuratorFramework clientStart(){
    		//连接时间和重试次数
    		RetryPolicy retryPolicy = new ExponentialBackoffRetry(1000, 3);
    		client = CuratorFrameworkFactory.newClient(connectString, retryPolicy);
    		client.start();
    		return client;
    	}
    	
    	/**
    	 * 添加一个节点
    	 */
    	public static void testAdd(){
    		String addPath = "/zkAddByCurator";
    		try {
    			Stat checkStat = client.checkExists().forPath(addPath);
    			if (checkStat == null) {
    				client.create().forPath(addPath);
    				client.setData().forPath(addPath,"通过Curator自动添加".getBytes("UTF-8"));
    			}else {
    				System.out.println(addPath + "路径已经存在");
    			}
    			addPath = "/zkTmpAdd";
    			checkStat = client.checkExists().forPath(addPath);
    			if (checkStat == null) {
    				System.out.println(addPath + "路径尚不存在");
    				client.create().withMode(CreateMode.EPHEMERAL).forPath(addPath,"temp add then delete it by zk".getBytes());
    			}else {
    				System.out.println(addPath + "路径已经存在");
    			}
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    	
    	/**
    	 * 显示当前节点和子节点
    	 */
    	public static void testListSub(){
    		try {
    			List<String> subNodes = client.getChildren().forPath("/");
    			System.out.println("当前节点和子节点：" + subNodes);
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    	
    	/**
    	 * 实现CRUD及监听
    	 * @param client
    	 * @throws Exception
    	 */
    	public static void setListenterForCluster(CuratorFramework client) throws Exception{
    		ExecutorService pool = Executors.newCachedThreadPool();
    		PathChildrenCache childrenCache = new PathChildrenCache(client, rootPath, true);
    		PathChildrenCacheListener childrenCacheListener = new PathChildrenCacheListener() {
    			
    			@Override
    			public void childEvent(CuratorFramework client, PathChildrenCacheEvent event)
    					throws Exception {
    				ChildData data = event.getData();
    				switch (event.getType()) {
    					case CHILD_UPDATED:{
    						System.out.println("CHILD_UPDATED:" + data.getPath() + "，数据:" + new String(data.getData()));
    						break;
    					}
    					case CHILD_ADDED:{
    						String realPath = data.getPath().substring(rootPath.length());
    						if (realPath.equals(ghPath)) {
    							System.out.println(ghPath + "新节点添加");
    						}else if (realPath.equals(tmpPath)) {
    							System.out.println(tmpPath + "新节点添加");
    						}
    						System.out.println("CHILD_ADDED:" + data.getPath() + "，数据:" + new String(data.getData()));
    						break;
    					}
    					case CHILD_REMOVED:{
    						String realPath = data.getPath().substring(rootPath.length());
    						if (realPath.equals(ghPath)) {
    							System.out.println(ghPath + "新节点删除");
    						}else if (realPath.equals(tmpPath)) {
    							System.out.println(tmpPath + "新节点删除");
    						}
    						System.out.println("CHILD_REMOVED:" + data.getPath() + "，数据:" + new String(data.getData()));
    						break;
    					}
    					default:
    						break;
    				}
    				
    			}
    		};
    		childrenCache.getListenable().addListener(childrenCacheListener);
    		System.out.println("Register zk watcher successfully!!!");
    		childrenCache.start(StartMode.POST_INITIALIZED_EVENT);
    	}
    	
    	public static void main(String[] args) throws Exception {
    		CuratorFramework client = clientStart();
    		testAdd();
    		testListSub();
    		setListenterForCluster(client);
    		Thread.sleep(Long.MAX_VALUE);
    	}
    
    }

四、测试结果

（1）

![70 3][]

![70 4][]

（2）

![70 5][]

![70 6][]

至此，基于zkdash下Zookeeper完成CRUD及监听就讲解完了，是不是感觉也没有那么难，快点动手试一下吧。

你们在此过程中还遇到了什么问题，欢迎留言，让我看看你们都遇到了哪些问题。

[Hadoop]: http://blog.csdn.net/gdkyxy2013/article/details/79519152
[Zookeeper]: http://blog.csdn.net/gdkyxy2013/article/details/79519706
[Linux_MySQL]: http://blog.csdn.net/gdkyxy2013/article/details/79519940
[Hadoop_zkdash]: http://blog.csdn.net/gdkyxy2013/article/details/79520119
[70]: /images/20210726/4259dfef1e944042adde24e50a0c6f95.png
[70 1]: /images/20210726/df773441c06f4925a66ffac283b0b20c.png
[70 2]: /images/20210726/d702adc8abbc4e5788f9dc30a1372306.png
[70 3]: /images/20210726/ea06319f604e4329a30917e2fdef9521.png
[70 4]: /images/20210726/fb8c9156a3844224a516d4875b8b84b9.png
[70 5]: /images/20210726/59f85456e72a4af19f5cf36f16263127.png
[70 6]: /images/20210726/c977e3c292584eb0a984ded3cf2a4200.png