Zookeeper实现CRUD案例

短命女 2024-04-18 14:20 73阅读 0赞

### 一、引入pom ###

<dependencies>
            <dependency>
                <groupId>org.apache.zookeeper</groupId>
                <artifactId>zookeeper</artifactId>
                <version>3.4.6</version>
            </dependency>
        </dependencies>

### 二、实现案例  ###

package com.zhq;
    
    import org.apache.zookeeper.*;
    import org.apache.zookeeper.data.Stat;
    
    import java.util.concurrent.CountDownLatch;
    
    /**
     * @program: zookeeper
     * @description:
     * @author: HQ Zheng
     * @create: 2019-09-07 22:31
     */
    public class ZKWatcher implements Watcher {
        // 集群连接地址
        private static final String CONNECT_ADDRESS = "192.168.43.104:2181";
        // 会话超时时间
        private static final int SESSION_TIME = 2000;
        // 信号量,让zk在连接之前等待,连接成功后才能往下走.
        private static final CountDownLatch countDownLatch = new CountDownLatch(1);
        private static String LOG_MAIN = "【main】 ";
        private ZooKeeper zk;
    
        public void createConnection(String connectAddres, int sessionTimeOut) {
            try {
                zk = new ZooKeeper(connectAddres, sessionTimeOut, this);
                System.out.println(LOG_MAIN + "zk 开始启动连接服务器....");
                countDownLatch.await();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        public boolean createPath(String path, String data) {
            try {
                this.exists(path, true);
                this.zk.create(path, data.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
                System.out.println(LOG_MAIN + "节点创建成功, Path:" + path + ",data:" + data);
            } catch (Exception e) {
                e.printStackTrace();
                return false;
            }
            return true;
        }
    
        /**
         * 判断指定节点是否存在
         *
         * @param path
         * 节点路径
         */
        public Stat exists(String path, boolean needWatch) {
            try {
                return this.zk.exists(path, needWatch);
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        }
    
        public boolean updateNode(String path,String data) throws KeeperException, InterruptedException {
            exists(path, true);
            this.zk.setData(path, data.getBytes(), -1);
            return false;
        }
    
        //zk节点发生CRUDE事件监听
        public void process(WatchedEvent watchedEvent) {
    
            // 获取事件状态
            Event.KeeperState keeperState = watchedEvent.getState();
            // 获取事件类型
            Event.EventType eventType = watchedEvent.getType();
            // zk 路径
            String path = watchedEvent.getPath();
            System.out.println("进入到 process() keeperState:" + keeperState + ", eventType:" + eventType + ", path:" + path);
            // 判断是否建立连接
            if (Event.KeeperState.SyncConnected == keeperState) {
                if (Event.EventType.None == eventType) {
                    // 如果建立建立成功,让后程序往下走
                    System.out.println(LOG_MAIN + "zk 建立连接成功!");
                    countDownLatch.countDown();
                } else if (Event.EventType.NodeCreated == eventType) {
                    System.out.println(LOG_MAIN + "事件通知,新增node节点" + path);
                } else if (Event.EventType.NodeDataChanged == eventType) {
                    System.out.println(LOG_MAIN + "事件通知,当前node节点" + path + "被修改....");
                }
                else if (Event.EventType.NodeDeleted == eventType) {
                    System.out.println(LOG_MAIN + "事件通知,当前node节点" + path + "被删除....");
                }
    
            }
            System.out.println("--------------------------------------------------------");
        }
    
        public static void main(String[] args) throws KeeperException, InterruptedException {
            ZKWatcher zkClientWatcher = new ZKWatcher();
            zkClientWatcher.createConnection(CONNECT_ADDRESS, SESSION_TIME);
            boolean createResult = zkClientWatcher.createPath("/test", "first-node");
        }
    
    }

### 三、运行测试  ###

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