curator框架与zkclient操作zookeeper,简化复杂原生API

打开zookeeper集群

先体会一下原生API有多麻烦(可略过):

//地址
    static final String ADDR = "192.168.171.128:2181,192.168.171.129:2181,192.168.171.130:2181";
    //session超时时间
    static final int SESSION_OUTTIME = 2000;//ms
    /**
     * 信号量，阻塞程序执行，用于等待zookeeper连接(异步的)成功，发送成功信号
     */
    static final CountDownLatch connectedSemaphore = new CountDownLatch(1);

    public static void main(String[] args) throws Exception {
        //创建zk客户端(异步连接)   Watcher:监听连接
        ZooKeeper zooKeeper = new ZooKeeper(ADDR, SESSION_OUTTIME, new Watcher() {
            @Override
            public void process(WatchedEvent watchedEvent) {
                //获取事件的状态
                Event.KeeperState keeperState = watchedEvent.getState();
                Event.EventType eventType = watchedEvent.getType();
                //如果是建立连接
                if(Event.KeeperState.SyncConnected == keeperState){
                    if(Event.EventType.None == eventType){
                        //如果建立连接成功，则发送信号量，让后续阻塞程序向下执行
                        connectedSemaphore.countDown();
                        System.out.println("zk 建立连接");
                    }
                }
            }
        });
        //进行阻塞,等待zk连接成功
        connectedSemaphore.await();
        //连接成功执行操作:
        //同步     路径(不允许递归创建), 数据  权限, 类型(PERSISTENT:持久) :临时节点只是一次session有效,用来实现分布式锁
        String name = zooKeeper.create("/testRoot", "test".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
        String name1 = zooKeeper.create("/testRoot/child02", "test".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
        //异步   回调函数   , 回调的参数
        zooKeeper.create("/testRoot/child01", "test".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT,
                new AsyncCallback.StringCallback() {
                    @Override   //服务端响应吗: 0 成功   传入的path   参数  实际创建的path
                    public void processResult(int i, String s, Object o, String s1) {
                        System.out.println(i+" "+s+" "+o.toString()+" "+s1); }},"param");
        //删除 (路径必须是叶子节点,即没有下一级节点,不支持递归)
        //zooKeeper.delete("/testRoot/child01", -1);//版本号:-1表示删除所有的,像git一样,修改一次版本号加一,可删除指定版本号
        //同样支持异步,和创建一样传入回调
        //判断节点是否存在
        System.out.println(zooKeeper.exists("/testRoot/child01", false));//也可传入watch,异步回调等
        //获取
        byte[] data = zooKeeper.getData("/testRoot", false, null);
		System.out.println(new String(data));
		System.out.println(zooKeeper.getChildren("/testRoot", false));
        //修改
        zooKeeper.setData("/testRoot", "modify data root".getBytes(), -1);
		byte[] data1 = zooKeeper.getData("/testRoot", false, null);
		System.out.println(new String(data1));


        Thread.sleep(3000);//休眠防止异步
        zooKeeper.close();//释放资源

　　

zkclient:

　　/** zookeeper地址 */
    static final String CONNECT_ADDR = "192.168.171.128:2181,192.168.171.129:2181,192.168.171.130:2181";
    /** session超时时间 */
    static final int SESSION_OUTTIME = 5000;//ms

    public static void main(String[] args) {
        // 创建zkclient实例
        ZkClient zkc=new ZkClient(new ZkConnection(CONNECT_ADDR,SESSION_OUTTIME),10000);
        //增
        zkc.create("/test","测试zkclient",CreateMode.PERSISTENT);// 创建节点,可指定持久或者临时
        zkc.create("/test/heyi","heyi",CreateMode.PERSISTENT);// 创建节点,可指定持久或者临时
        zkc.createEphemeral("/haha","haha");//创建临时节点
        zkc.createPersistent("/test/yaozhen","姚振");//创建持久节点,设置值必须有父节点
        zkc.createPersistent("/320/houzheng",true);//支持递归创建,但是不能设置值,否则会报异常
        //删
        zkc.delete("/test/yaozhen");
        zkc.deleteRecursive("/320");//递归删除,会删除节点下的子节点
        //改
        zkc.writeData("/test","新内容");
        //查
        boolean exists = zkc.exists("/test");
        System.out.println(exists);
        zkc.readData("/jim",true);//如果节点为空返回null
        String readData = zkc.readData("/test");
        System.out.println(readData);
        //获取子节点和阅读子节点数据
        List<String> list = zkc.getChildren("/test");
        for(String p : list){
            System.out.println(p);
            String rp = "/test/" + p;
            String data = zkc.readData(rp);
            System.out.println("节点为：" + rp + "，内容为: " + data);
        }
        int i = zkc.countChildren("/test");//查询子节点数量
        System.out.println(i);

　　相比之下zkclient简直太简单了!

watcher也特别简单:

子节点监听:

// 创建zkclient实例
        ZkClient zkClient=new ZkClient(new ZkConnection(CONNECT_ADDR,SESSION_OUTTIME),10000);
        System.out.println("-----------");
        //监听子节点变化(不监听数据变化,只监听节点的新增删除)  IZkChildListener实现类
        zkClient.subscribeChildChanges("/father",(x,y)->{//x:父路径, y:所有子节点路径集合
            System.out.println("parentPath: " + x);
            System.out.println("currentChilds: " + y);
        });
        Thread.sleep(2000);
        zkClient.createPersistent("/father");//父节点添加删除也会监听
        Thread.sleep(1000);
        zkClient.createPersistent("/father/son","儿子");
        Thread.sleep(1000);
        zkClient.createPersistent("/father/daughter","女儿");
        Thread.sleep(1000);
        zkClient.delete("/father/son");
        Thread.sleep(1000);
        zkClient.deleteRecursive("/father");

　　

节点数据监听:

        //监听节点数据变化,监听之前节点必须存在,不监听子节点
        zkClient.createPersistent("/father", "1234");
        zkClient.subscribeDataChanges("/father", new IZkDataListener() {
            @Override   //节点数据变化
            public void handleDataChange(String s, Object o) throws Exception {
                System.out.println("变更的节点为:" + s + ", 变更内容为:" + o);
            }
            @Override  //节点删除
            public void handleDataDeleted(String s) throws Exception {
                System.out.println("删除的节点为:" + s);
            }
        });
        Thread.sleep(3000);
        zkClient.writeData("/father", "father");//-1:最新版本的数据
        Thread.sleep(1000);
        zkClient.delete("/father");//节点删除野人不监听
        Thread.sleep(1000);

　　

状态监听:

        //监听服务连接状态,可手动启动关闭zookeeper查看触发
        zkClient.subscribeStateChanges(new IZkStateListener() {
            @Override
            public void handleStateChanged(Watcher.Event.KeeperState state) throws Exception {
                if(state==Watcher.Event.KeeperState.SyncConnected){
                    System.out.println("连接zookeeper成功");
                }else if(state==Watcher.Event.KeeperState.Disconnected){
                    System.out.println("zookeeper断开");
                }else
                    System.out.println("other"+state);
            }
            @Override //连接关闭,过了session的设置时间,再连接session就会重置,触发监听
            public void handleNewSession() throws Exception {
                System.out.println("newsession");
            }
        });
        Thread.sleep(Integer.MAX_VALUE);//用不关闭线程,一直监听

　　

curator框架: