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zookeeper java的API 入门使用

作者:互联网

一.创建简单的maven项目导包 org.apache.zookeeper zookeeper 3.6.3 二。编辑 代码 package com.wqj; import org.apache.zookeeper.*; import org.apache.zookeeper.data.Stat; import java.util.concurrent.CountDownLatch; /** * Hello world! * */ public class App { //连接字符串。zk server zkConnectString地址和端口 private static String zkConnectString ="192.168.0.133:2181,192.168.0.134:2181,192.168.0.135:2181"; // 会话超时时间 单位ms private static int sessionTimeout =3000; //监视器对象 public static void main( String[] args ) throws Exception { System.out.println( "Hello World!" ); //1.创建zk对象 /* //zk有session的概念,没有连接池的概念 //watch: 观察回调,回调。 //watch的注册值发生在 读类型调用 //第一类:new zk 时候,传入的watch,这个watch,session级别的,跟path 、node没有关系 ZooKeeper(String connectString, int sessionTimeout, Watcher watcher) 第一个参数: zookeeper服务器的地址 第二个参数: 超时时间一般为心跳时间的2倍 第三个参数: 该对象用来处理zookeeper服务器响应的事件 */ //加锁同步执行 final CountDownLatch countDownLatch = new CountDownLatch(1); final ZooKeeper zk = new ZooKeeper(zkConnectString, sessionTimeout, new Watcher() { //默认watcher /* * 回调函数: * 当我们需要监听的事件发生以后,那么zookeeper服务器就会调用该方法。 * 当前这个构造器中的该对象是用来响应所有的事件。 * */ @Override public void process(WatchedEvent event) { //获取数据KeeperStatus通知状态 Event.KeeperState state = event.getState(); //获取EventType事件类型 Event.EventType type = event.getType(); //获取地址 String path = event.getPath(); System.out.println("new zk path(创建 zk 连接获取地址:) " +path); //判断数据类型 KeeperStatus通知状态 //switch (state) + 快捷键 Alt +enter switch (state) { case Unknown: break; case Disconnected: break; case NoSyncConnected: break; case SyncConnected: System.out.println("connected(连接创建成功):"); countDownLatch.countDown(); break; case AuthFailed: break; case ConnectedReadOnly: break; case SaslAuthenticated: break; case Expired: break; case Closed: break; } switch (type) { case None: break; case NodeCreated: break; case NodeDeleted: break; case NodeDataChanged: break; case NodeChildrenChanged: break; case DataWatchRemoved: break; case ChildWatchRemoved: break; case PersistentWatchRemoved: break; } } }); countDownLatch.await(); final ZooKeeper.States state = zk.getState(); switch (state) { case CONNECTING: System.out.println("CONNECTING---------------"); break; case ASSOCIATING: System.out.println("ASSOCIATING------------"); break; case CONNECTED: break; case CONNECTEDREADONLY: break; case CLOSED: break; case AUTH_FAILED: break; case NOT_CONNECTED: break; } /*** * final String path, * byte[] data, * List acl, 权限 * OPEN_ACL_UNSAFE : 完全开放的ACL,任何连接的客户端都可以操作该属性znode * CREATOR_ALL_ACL : 只有创建者才有ACL权限 * READ_ACL_UNSAFE:只能读取ACL * CreateMode createMode 节点类型 临时 */ String pathName = zk.create("/wqj", "wqj_wqj".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL); final Stat stat = new Stat(); byte[] node = zk.getData("/wqj", new Watcher() { @Override public void process(WatchedEvent event) { System.out.println("getData watch:--------------"+event.toString()); // System.out.println("没有回调----"); try { zk.getData("/wqj",this,stat); } catch (KeeperException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } } },stat); System.out.println("node---"+new String(node)); /** 触发回调 * final String path, * byte[] data, * int version 版本 ,每一次不同 */ Stat stat01 = zk.setData("/wqj", "wqj_0112".getBytes(), 0); //还会回调吗? 还会的 Stat stat02 = zk.setData("/wqj", "wqj_011".getBytes(), stat01.getVersion()); System.out.println("-------async start----------"); zk.getData("/wqj", false, new AsyncCallback.DataCallback() { @Override public void processResult(int rc, String path, Object ctx, byte[] data, Stat stat) { System.out.println("-------async call back----------"); System.out.println(ctx.toString()); System.out.println(new String(data)); } },"wqjj"); System.out.println("-------async over----------"); Thread.sleep(2222); } }

标签:case,java,zk,zookeeper,System,break,API,println,out
来源: https://www.cnblogs.com/wqj-grh/p/16584091.html