Zookeeper 之使用Curator 來操作數據存儲和事件監聽

Curator高度封裝zookeeper客戶端，對比之前的原生就非常nice。

碼來！～～～

首先還是pom文件下載jar包

<dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>4.0.1</version>
        </dependency>

 

增、刪、改如下 查就是stat，namespace也會自動創建出來。

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.data.Stat;

/**
 * @Title: Spring-distributed
 * @Description:
 * @author: liaryank
 * @Date: 2020/5/6 11:26 上午
 * @Version: 1.0
 */
public class Curator {

    public static void main(String[] args) throws Exception {
        CuratorFramework curatorFramework = CuratorFrameworkFactory.builder().connectString("192.168.3.32,192.168.3.33,192.168.3.34")
                .sessionTimeoutMs(4000).
                        //重試機制
                retryPolicy(new ExponentialBackoffRetry(1000,3)).namespace("Curator").build();

        curatorFramework.start();
        //創建 會把上面的namespace和下面的父子節點都創建出來
        curatorFramework.create().creatingParentsIfNeeded().
                withMode(CreateMode.PERSISTENT).
                forPath("/liaryank/node","1".getBytes());
        //修改
        Stat stat = new Stat();
        curatorFramework.getData().storingStatIn(stat).forPath("/liaryank/node");
        curatorFramework.setData().withVersion(stat.getVersion()).forPath("/liaryank/node","abc".getBytes());
        //刪除 刪除就寫入你要刪除的節點路徑就好
        curatorFramework.delete().deletingChildrenIfNeeded().
                forPath("/liaryank/node");

        curatorFramework.close();
    }

}

 自己創建、刪除、修改註釋下多試試然後用客戶端檢查一下操作結果

相比與之前的原生就舒服多了，簡潔明瞭，而且多層級快速構建。

下面我們來演示一下監聽機制：

首先引入一下jar包

<dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>4.0.1</version>
        </dependency>

下面有三個方法

調用時逐個註釋觀察，你就會發現其中的奧妙。

package com.test.demo1;

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.cache.*;
import org.apache.curator.retry.ExponentialBackoffRetry;


/**
 * @Title: Spring-distributed
 * @Description:增刪改和事務監聽
 * @author: liaryank
 * @Date: 2020/5/6 11:26 上午
 * @Version: 1.0
 */
public class Curator {

    public static void main(String[] args) throws Exception {
        CuratorFramework curatorFramework = CuratorFrameworkFactory.builder().connectString("192.168.3.32,192.168.3.33,192.168.3.34")
                .sessionTimeoutMs(4000).
                        //重試機制
                retryPolicy(new ExponentialBackoffRetry(1000,3)).namespace("Curator").build();

        curatorFramework.start();
        //監聽當前這個節點的增刪改
        //ListenerNodeCache(curatorFramework,"/liaryank");
        //監聽當前這個節點的子節點的增刪改
        //ListenerPathChildCache(curatorFramework,"/liaryank");
        //監聽當前節點及子節點的增刪改
        TreeNode(curatorFramework,"/liaryank");
        System.in.read();
    }

    /***
     * PatchChildCache 監聽一個節點下的子節點創建、更新、刪除
     * NodeCache 監聽一個節點的更新和創建事件
     * TreeNode 綜合PatchChildCache 、NodeCache特性
     */

    public static void ListenerPathChildCache(CuratorFramework curatorFramework, String path) throws Exception {
        PathChildrenCache pathChildrenCache = new PathChildrenCache(curatorFramework,path,true);
        PathChildrenCacheListener pathChildrenCacheListener = new PathChildrenCacheListener() {
            @Override
            public void childEvent(CuratorFramework curatorFramework, PathChildrenCacheEvent pathChildrenCacheEvent) throws Exception {
                System.out.println("Receive Event:"+ pathChildrenCacheEvent.getType());
            }
        };
        pathChildrenCache.getListenable().addListener(pathChildrenCacheListener);
        pathChildrenCache.start(PathChildrenCache.StartMode.NORMAL);
    }

    public static void ListenerNodeCache(CuratorFramework curatorFramework, String path) throws Exception {
        final NodeCache nodeCache = new NodeCache(curatorFramework,path,false);
        NodeCacheListener nodeCacheListener = new NodeCacheListener() {
            @Override
            public void nodeChanged() throws Exception {
                System.out.println("Receive Event:"+nodeCache.getCurrentData().getPath());
            }
        };
        nodeCache.getListenable().addListener(nodeCacheListener);
        nodeCache.start();
    }

    public static void TreeNode(CuratorFramework curatorFramework, String path) throws Exception {
        TreeCache treeCache = new TreeCache(curatorFramework, path);
        TreeCacheListener treeCacheListener = new TreeCacheListener() {
            @Override
            public void childEvent(CuratorFramework curatorFramework, TreeCacheEvent treeCacheEvent) throws Exception {
                System.out.println(treeCacheEvent.getType()+"==>"+treeCacheEvent.getData().getPath());
            }
        };
        treeCache.getListenable().addListener(treeCacheListener);
        treeCache.start();
    }
}

操作截圖

 這種事件監聽是不是比原生的舒服多了，就很nice。