CuratorWatcherTest.java

package com.kwan.shuyu;

import org.apache.curator.RetryPolicy;
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;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class CuratorWatcherTest {
    private CuratorFramework client;

    /**
     * 建立连接
     */
    @Before
    public void testConnect() {
        /*
         *
         * @param connectString       连接字符串。zk server 地址和端口 "192.168.149.135:2181,192.168.149.136:2181"
         * @param sessionTimeoutMs    会话超时时间 单位ms
         * @param connectionTimeoutMs 连接超时时间 单位ms
         * @param retryPolicy         重试策略
         */
       /* //重试策略
        RetryPolicy retryPolicy = new ExponentialBackoffRetry(3000,10);
        //1.第一种方式
        CuratorFramework client = CuratorFrameworkFactory.newClient("192.168.149.135:2181",
                60 * 1000, 15 * 1000, retryPolicy);*/
        //重试策略
        RetryPolicy retryPolicy = new ExponentialBackoffRetry(3000, 10);
        //2.第二种方式
        //CuratorFrameworkFactory.builder();
        client = CuratorFrameworkFactory.builder()
                .connectString("192.168.149.135:2181")
                .sessionTimeoutMs(60 * 1000)
                .connectionTimeoutMs(15 * 1000)
                .retryPolicy(retryPolicy)
                .namespace("itheima")
                .build();
        //开启连接
        client.start();
    }

    @After
    public void close() {
        if (client != null) {
            client.close();
        }
    }

    /**
     * 演示 NodeCache：给指定一个节点注册监听器
     */
    @Test
    public void testNodeCache() throws Exception {
        //1. 创建NodeCache对象
        final NodeCache nodeCache = new NodeCache(client, "/app1");
        //2. 注册监听
        nodeCache.getListenable().addListener(new NodeCacheListener() {
            @Override
            public void nodeChanged() throws Exception {
                System.out.println("节点变化了~");
                //获取修改节点后的数据
                byte[] data = nodeCache.getCurrentData().getData();
                System.out.println(new String(data));
            }
        });
        //3. 开启监听.如果设置为true，则开启监听是，加载缓冲数据
        nodeCache.start(true);
        while (true) {
        }
    }

    /**
     * 演示 PathChildrenCache：监听某个节点的所有子节点们
     */
    @Test
    public void testPathChildrenCache() throws Exception {
        //1.创建监听对象
        PathChildrenCache pathChildrenCache = new PathChildrenCache(client, "/app2", true);
        //2. 绑定监听器
        pathChildrenCache.getListenable().addListener(new PathChildrenCacheListener() {
            @Override
            public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception {
                System.out.println("子节点变化了~");
                System.out.println(event);
                //监听子节点的数据变更，并且拿到变更后的数据
                //1.获取类型
                PathChildrenCacheEvent.Type type = event.getType();
                //2.判断类型是否是update
                if (type.equals(PathChildrenCacheEvent.Type.CHILD_UPDATED)) {
                    System.out.println("数据变了！！！");
                    byte[] data = event.getData().getData();
                    System.out.println(new String(data));
                }
            }
        });
        //3. 开启
        pathChildrenCache.start();
        while (true) {
        }
    }

    /**
     * 演示 TreeCache：监听某个节点自己和所有子节点们
     */
    @Test
    public void testTreeCache() throws Exception {
        //1. 创建监听器
        TreeCache treeCache = new TreeCache(client, "/app2");
        //2. 注册监听
        treeCache.getListenable().addListener(new TreeCacheListener() {
            @Override
            public void childEvent(CuratorFramework client, TreeCacheEvent event) throws Exception {
                System.out.println("节点变化了");
                System.out.println(event);
            }
        });
        //3. 开启
        treeCache.start();
        while (true) {
        }
    }
}