zookeeper获取所有节点——基于curator框架

本文主要介绍基于curator框架访问zookeeper所有节点。

本文主要参考：

https://github.com/Netflix/curator

http://curator.apache.org/

好，下面上货。

1、首先创建一个maven工程

mvn archetype:generate -DarchetypeCatalog=internal

2、添加依赖：

<!-- https://mvnrepository.com/artifact/org.apache.curator/curator-framework -->        <dependency>            <groupId>org.apache.curator</groupId>            <artifactId>curator-framework</artifactId>            <version>4.0.0</version>            <exclusions>                <exclusion>                    <groupId>org.apache.zookeeper</groupId>                    <artifactId>zookeeper</artifactId>                </exclusion>            </exclusions>        </dependency>        <dependency>            <groupId>org.apache.zookeeper</groupId>            <artifactId>zookeeper</artifactId>            <version>3.4.10</version>        </dependency>

3、看一下工程结构：

4、zkUtils中的内容：

CreateClient.java

package com.xueyou.zkdemo.zkUtils;import org.apache.curator.RetryPolicy;import org.apache.curator.framework.CuratorFramework;import org.apache.curator.framework.CuratorFrameworkFactory;import org.apache.curator.retry.ExponentialBackoffRetry;public class CreateClient {    public static CuratorFramework createSimple(String connectionString) {        // these are reasonable arguments for the ExponentialBackoffRetry. The first        // retry will wait 1 second - the second will wait up to 2 seconds - the        // third will wait up to 4 seconds.        ExponentialBackoffRetry retryPolicy = new ExponentialBackoffRetry(1000, 3);        // The simplest way to get a CuratorFramework instance. This will use default values.        // The only required arguments are the connection string and the retry policy        return CuratorFrameworkFactory.newClient(connectionString, retryPolicy);    }    public static CuratorFramework createWithOptions(String connectionString, RetryPolicy retryPolicy, int connectionTimeoutMs, int sessionTimeoutMs) {        // using the CuratorFrameworkFactory.builder() gives fine grained control        // over creation options. See the CuratorFrameworkFactory.Builder javadoc        // details        return CuratorFrameworkFactory.builder()                .connectString(connectionString)                .retryPolicy(retryPolicy)                .connectionTimeoutMs(connectionTimeoutMs)                .sessionTimeoutMs(sessionTimeoutMs)                // etc. etc.                .build();    }}

CuratorZkClientBridge.java

package com.xueyou.zkdemo.zkUtils;import org.apache.curator.framework.CuratorFramework;import org.apache.curator.framework.api.BackgroundCallback;import org.apache.curator.framework.api.CuratorEvent;import org.apache.curator.framework.api.CuratorListener;import org.apache.zookeeper.CreateMode;import org.apache.zookeeper.KeeperException;import org.apache.zookeeper.WatchedEvent;import org.apache.zookeeper.Watcher;import org.apache.zookeeper.ZooKeeper;import org.apache.zookeeper.data.Stat;import java.util.List;import java.util.concurrent.atomic.AtomicReference;public class CuratorZkClientBridge {    private final CuratorFramework curator;    private final AtomicReference<CuratorListener> listener = new AtomicReference<CuratorListener>(null);    /**     * @param curator Curator instance to bridge     */    public CuratorZkClientBridge(CuratorFramework curator)    {        this.curator = curator;    }    /**     * Return the client     *     * @return client     */    public CuratorFramework getCurator()    {        return curator;    }    public void connect(final Watcher watcher)    {        if ( watcher != null )        {            CuratorListener     localListener = new CuratorListener()            {                public void eventReceived(CuratorFramework client, CuratorEvent event) throws Exception                {                    if ( event.getWatchedEvent() != null )                    {                        watcher.process(event.getWatchedEvent());                    }                }            };            curator.getCuratorListenable().addListener(localListener);            listener.set(localListener);            try            {                BackgroundCallback callback = new BackgroundCallback()                {                    public void processResult(CuratorFramework client, CuratorEvent event) throws Exception                    {                        WatchedEvent        fakeEvent = new WatchedEvent(Watcher.Event.EventType.None, curator.getZookeeperClient().isConnected() ? Watcher.Event.KeeperState.SyncConnected : Watcher.Event.KeeperState.Disconnected, null);                        watcher.process(fakeEvent);                    }                };                curator.checkExists().inBackground(callback).forPath("/foo");            }            catch ( Exception e )            {                throw new RuntimeException(e);            }        }    }    public void close() throws InterruptedException    {        // NOTE: the curator instance is NOT closed here        CuratorListener localListener = listener.getAndSet(null);        if ( localListener != null )        {            curator.getCuratorListenable().removeListener(localListener);        }    }    public String create(String path, byte[] data, CreateMode mode) throws KeeperException, InterruptedException    {        try        {            return curator.create().withMode(mode).forPath(path, data);        }        catch ( Exception e )        {            adjustException(e);        }        return null;    // will never execute    }    public void delete(String path) throws InterruptedException, KeeperException    {        try        {            curator.delete().forPath(path);        }        catch ( Exception e )        {            adjustException(e);        }    }    public boolean exists(String path, boolean watch) throws KeeperException, InterruptedException    {        try        {            return watch ? (curator.checkExists().watched().forPath(path) != null) : (curator.checkExists().forPath(path) != null);        }        catch ( Exception e )        {            adjustException(e);        }        return false;   // will never execute    }    public List<String> getChildren(String path, boolean watch) throws KeeperException, InterruptedException    {        try        {            return watch ? curator.getChildren().watched().forPath(path) : curator.getChildren().forPath(path);        }        catch ( Exception e )        {            adjustException(e);        }        return null;   // will never execute    }    public byte[] readData(String path, Stat stat, boolean watch) throws KeeperException, InterruptedException    {        try        {            if ( stat != null )            {                return watch ? curator.getData().storingStatIn(stat).watched().forPath(path) : curator.getData().storingStatIn(stat).forPath(path);            }            else            {                return watch ? curator.getData().watched().forPath(path) : curator.getData().forPath(path);            }        }        catch ( Exception e )        {            adjustException(e);        }        return null;   // will never execute    }    public void writeData(String path, byte[] data, int expectedVersion) throws KeeperException, InterruptedException    {        writeDataReturnStat(path, data, expectedVersion);    }    public Stat writeDataReturnStat(String path, byte[] data, int expectedVersion) throws KeeperException, InterruptedException {        try        {            curator.setData().withVersion(expectedVersion).forPath(path, data);        }        catch ( Exception e )        {            adjustException(e);        }        return null; // will never execute    }    public ZooKeeper.States getZookeeperState()    {        try        {            return curator.getZookeeperClient().getZooKeeper().getState();        }        catch ( Exception e )        {            throw new RuntimeException(e);        }    }    public long getCreateTime(String path) throws KeeperException, InterruptedException    {        try        {            Stat            stat = curator.checkExists().forPath(path);            return (stat != null) ? stat.getCtime() : 0;        }        catch ( Exception e )        {            adjustException(e);        }        return 0;    }    public String getServers()    {        return curator.getZookeeperClient().getCurrentConnectionString();    }    private void adjustException(Exception e) throws KeeperException, InterruptedException    {        if ( e instanceof KeeperException )        {            throw (KeeperException)e;        }        if ( e instanceof InterruptedException )        {            throw (InterruptedException)e;        }        throw new RuntimeException(e);    }}

5、例子程序，遍历zookeeper所有节点。

package com.xueyou.zkdemo;import com.xueyou.zkdemo.zkUtils.CreateClient;import com.xueyou.zkdemo.zkUtils.CuratorZkClientBridge;import org.apache.curator.framework.CuratorFramework;import org.apache.zookeeper.KeeperException;import java.util.ArrayList;import java.util.List;/** * Hello world! */public class App {    public static String connectionString = "192.168.0.99:2181,192.168.0.99:2182,192.168.0.99:2183";    public static List<String> res = new ArrayList<>();    public static void main(String[] args) {        System.out.println("Hello World!");        CuratorFramework curatorFramework = CreateClient.createSimple(connectionString);        curatorFramework.start();        //doSomething to zookeeper        CuratorZkClientBridge curatorZkClientBridge = new CuratorZkClientBridge(curatorFramework);        System.out.println(getNode(curatorZkClientBridge, "/"));        curatorFramework.close();    }    public static List<String> getNode(CuratorZkClientBridge curatorZkClientBridge, String parentNode) {        try {            List<String> tmpList = curatorZkClientBridge.getChildren(parentNode, false);            for (String tmp : tmpList) {                String childNode = parentNode.equals("/") ? parentNode + tmp : parentNode + "/" + tmp;                res.add(childNode);                getNode(curatorZkClientBridge, childNode);            }            return res;        } catch (KeeperException e) {            e.printStackTrace();            return null;        } catch (InterruptedException e) {            e.printStackTrace();            return null;        }    }}

6、运行结果：