Curator实现zookeeper的节点监听详解

目录

• Curator实现zookeeper的节点监听
• Watch监听之NodeCache
• Watch监听之PathChildrenCache
• watch监听之TreeCache
• 完整代码

Curator实现zookeeper的节点监听

Curtor框架中一共有三个实现监听的方式 一种是NodeCache监听指定节点 一种是pathChildrenCache监听子节点 一种是TreeCache可以监控所有节点 相当于以上两种的合集

引入依赖

        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>4.3.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-client</artifactId>
            <version>4.3.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>4.3.0</version>
        </dependency>

创建一个测试类 连接好客户端

public class CuratorTest {
    private CuratorFramework curatorFramework;
    @Before
    public void testCreate() {
        ExponentialBackoffRetry retry = new ExponentialBackoffRetry(2, 10);
        curatorFramework = CuratorFrameworkFactory.builder()
                .connectString("127.0.0.1:2181")
                .connectionTimeoutMs(60 * 1000)
                .sessionTimeoutMs(15 * 10000)
                .retryPolicy(retry).build();
        curatorFramework.start();
    }
   @After
    public void close() {
        if (curatorFramework != null) {
            curatorFramework.close();
        }
    }
}

Watch监听之NodeCache

监听一个指定节点

 @Test
    public void testUpdate() throws Exception {
        //监听一个节点
        NodeCache nodeCamqMJzZche = new NodeCache(curatorFramework,"/dongwuyuan");
        //注册监听
        nodeCache.getListenable().addListener(new NodeCacheListener() {
            @Override
            public void nodeChanged() throws Exception {
                System.out.println("节点变化了！！！！");
            }
        });
        //开启监听 参数 如果设置为true 则开启监听时加载缓存数据
        nodeCache.start(true);
        while (true){
        }
    }

set /dongwuyuan "laohu"

Watch监听之PathChildrenCache

监听子节点的变化

 @Test
    public void testPathChildrenCache() throws Exception {
        // 参数  客户端，路径 ，缓存数据，是否压缩，线程池
        PathChildrenCache pathChildrenCache = new PathChildrenCache(curatorFramework,"/dongwuyuan",pythontrue);
        //绑定监听器
        pathChildrenCache.getListenable().addListener(new PathChildrenCacheListener() {
            @Override
            public void childEvent(CuratorFramework curatorFramework, PathChildrenCacheEvent pathChildrenCacheEvent) throws Exception {
                System.out.println("子节点变化了");
                System.out.println(pathChildrenCacheEvent);
                //监听子节点的变更,并且拿到变更后的数据
                PathChildrenCacheEvent.Type type = pathChildrenCacheEvent.getType();
                //判断类型是否是update
                if(type.equals(PathChildrenCacheEvent.Type.CHILD_UPDATED)){
                     //拿到数据
                    byte[] data = pathChildrenCacheEvent.getData().getData();
                    System.out.println(data);
                }
            }
        });
        //开启监听
        pathChildrenCache.start();
        while (true){
        }
    }

watch监听之TreeCache

  /**
     * TreeCache:监听节点自己和所有子节点们
     */
    @Test
    public void testTreeCache(){
        //1.创建监听器
        TreeCache treeCache = new TreeCache(curatorFramework, "/dongwuyuan");
        //2.注册监python听
        treeCache.getListenable().addListener(new TreeCacheListener() {
            @Override
            public void childEvent(CuratorFramework client, jsTreeCacheEvent event) throws Exception {
                System.out.println("节点变化了");
                System.out.println(event);
            }
        });
        //开启监听
        try {
            treeCache.start();
            while (true){
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

[zk: localhost:2181(CONNECTED) 13] delete /dongwuyuan/node1

[zk: localhost:2181(CONNECTED) 15] set /dongwuyuan/node2  "shizi"

完整代码

public class CuratorTest {
    private CuratorFramework curatorFramework;
    @Before
    public void testCreate() {
        ExponentialBackoffRetry retry = new ExponentialBackoffRetry(2, 10);
        curatorFramework = CuratorFrameworkFactory.builder()
                .connectString("127.0.0.1:2181")
                .connectionTimeoutMs(60 * 1000)
                .sessionTimeoutMs(15 * 10000)
                .retryPolicy(retry).build();
        curatorFramework.start();
    }
    @Test
    public void testUpdate() throws Exception {
        //监听一个节点
        NodeCache nodeCache = new NodeCache(curatorFramework,"/dongwuyuan");
        //注册监听
        nodeCache.getListenable().addListener(new NodeCacheListener() {
            @Override
            pu编程客栈blic void nodeChanged() throws Exception {
                System.out.println("节点变化了！！！！");
            }
        });
        //开启监听 参数 如果设置为true 则开启监听时加载缓存数据
        nodeCache.start(true);
        while (true){
        }
    }
    @Test
    public void testPathChildrenCache() throws Exception {
        // 参数  客户端，路径 ，缓存数据，是否压缩，线程池
        PathChildrenCache pathChildrenCache = new PathChildrenCache(curatorFramework,"/dongwuyuan",true);
        //绑定监听器
        pathChildrenCache.getListenable().addListener(new PathChildrenCacheListener() {
            @Override
            public void childEvent(CuratorFramework curatorFramework, PathChildrenCacheEvent pathChildrenCacheEvent) throws Exception {
                System.out.println("子节点变化了");
                System.out.println(pathChildrenCacheEvent);
                //监听子节点的变更,并且拿到变更后的数据
                PathChildrenCacheEvent.Type type = pathChildrenCacheEvent.getType();
                //判断类型是否是update
                if(type.equals(PathChildrenCacheEvent.Type.CHILD_UPDATED)){
                     //拿到数据
                    byte[] data = pathChildrenCacheEvent.getData().getData();
                    System.out.println(data);
                }
            }
        });
        //开启监听
        pathChildrenCache.start();
        while (true){
        }
    }
    /**
     * TreeCache:监听节点自己和所有子节点们
     */
    @Test
    public void testTreeCache(){
        //1.创建监听器
        TreeCache treeCache = new TreeCache(curatorFramework, "/dongwuyuan");
        //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);
            }
        });
        //开启监听
        try {
            treeCache.start();
            while (true){
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @After
    public void close() {
        if (curatorFramework != null) {
            curatorFramework.close();
        }
    }
}

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