<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.6.0</version>
  </dependency>

//連接字符串,zkServer的ip、port，如果是集群逗號分隔
  String connectStr = "192.168.1.9:2181";

  //zookeeper就是一個zkCli
  ZooKeeper zooKeeper = null;

  try {
　　　　　//初始次數(shù)為1。后面要在內(nèi)部類中使用，三種寫法：1、寫成外部類成員變量，不用加final；2、作為函數(shù)局部變量，放在try外面，寫成final；3、寫在try中，不加final
  　　 CountDownLatch countDownLatch = new CountDownLatch(1);
    //超時時間ms，監(jiān)聽器
    zooKeeper = new ZooKeeper(connectStr, 5000, new Watcher() {
      public void process(WatchedEvent watchedEvent) {
        //如果狀態(tài)變成已連接
        if (watchedEvent.getState().equals(Event.KeeperState.SyncConnected)) {
          System.out.println("連接成功");
          //次數(shù)-1
          countDownLatch.countDown();
        }
      }
    });
    //等待，次數(shù)為0時才會繼續(xù)往下執(zhí)行。等待監(jiān)聽器監(jiān)聽到連接成功，才能操作zk
    countDownLatch.await();
  } catch (IOException | InterruptedException e) {
    e.printStackTrace();
  }


  //...操作zk。后面的demo都是寫在此處的


  //關(guān)閉連接
  try {
    zooKeeper.close();
  } catch (InterruptedException e) {
    e.printStackTrace();
  }

// 檢測節(jié)點(diǎn)是否存在

  // 同步方式
  Stat exists = null;
  try {
    //如果存在，返回節(jié)點(diǎn)狀態(tài)Stat；如果不存在，返回null。第二個參數(shù)是watch
    exists = zooKeeper.exists("/mall",false);
  } catch (KeeperException | InterruptedException e) {
    e.printStackTrace();
  }
  if (exists==null){
    System.out.println("節(jié)點(diǎn)不存在");
  }
  else {
    System.out.println("節(jié)點(diǎn)存在");
  }


  //異步回調(diào)
  zooKeeper.exists("/mall",false, new AsyncCallback.StatCallback() {
    //第二個是path znode路徑，第三個是ctx 后面?zhèn)魅雽?shí)參，第四個是znode的狀態(tài)
    public void processResult(int i, String s, Object o, Stat stat) {
      //如果節(jié)點(diǎn)不存在，返回的stat是null
      if (stat==null){
        System.out.println("節(jié)點(diǎn)不存在");
      }
      else{
        System.out.println("節(jié)點(diǎn)存在");
      }
    }
  // 傳入ctx，Object類型
  },null);

//創(chuàng)建節(jié)點(diǎn)

  //同步方式
  try {
    //數(shù)據(jù)要寫成byte[]，不攜帶數(shù)據(jù)寫成null；默認(rèn)acl權(quán)限使用ZooDefs.Ids.OPEN_ACL_UNSAFE；最后一個是節(jié)點(diǎn)類型，P是永久，E是臨時，S是有序
    zooKeeper.create("/mall", "abcd".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    System.out.println("已創(chuàng)建節(jié)點(diǎn)/mall");
    //如果節(jié)點(diǎn)已存在，會拋出異常
  } catch (KeeperException | InterruptedException e) {　　　　 System.out.println("創(chuàng)建節(jié)點(diǎn)/mall失敗，請檢查節(jié)點(diǎn)是否已存在");
    e.printStackTrace();
  }

  //異步回調(diào)
  zooKeeper.create("/mall", "abcd".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT, new AsyncCallback.Create2Callback(){
    //第二個path，第三個ctx，第四個節(jié)點(diǎn)狀態(tài)
    public void processResult(int i, String s, Object o, String s1, Stat stat) {
      //回調(diào)方式不拋出異常，返回的stat是創(chuàng)建節(jié)點(diǎn)的狀態(tài)，如果節(jié)點(diǎn)已存在，返回的stat是null
      if (stat==null){
        System.out.println("創(chuàng)建節(jié)點(diǎn)/mall失敗，請檢查節(jié)點(diǎn)是否已存在");
      }
      else {
        System.out.println("節(jié)點(diǎn)創(chuàng)建成功");
      }
    }
    //ctx實(shí)參
  },null);

//刪除節(jié)點(diǎn)

  //同步方式
  try {
    //第二個參數(shù)是版本號，-1表示可以是任何版本
    zooKeeper.delete("/mall1",-1);
    System.out.println("成功刪除節(jié)點(diǎn)/mall");
  } catch (InterruptedException | KeeperException e) {
    System.out.println("刪除節(jié)點(diǎn)/mall失敗");
    e.printStackTrace();
  }


  //異步回調(diào)
  zooKeeper.delete("/mall2", -1, new AsyncCallback.VoidCallback() {
    //第二個是path，第三個是ctx
    public void processResult(int i, String s, Object o) {
      
    }
  //
  //ctx實(shí)參
  },null);

//獲取子節(jié)點(diǎn)列表，List<String>，比如/mall/user,/mall/order，返回的是["user"、"order"]

  //同步方式
  List<String> children = null;
  try {
    //第二個參數(shù)是watch
    children = zooKeeper.getChildren("/mall", false);
  } catch (KeeperException | InterruptedException e) {
    e.printStackTrace();
  }
  System.out.println("子節(jié)點(diǎn)列表：" + children);


  //異步
  zooKeeper.getChildren("/mall", false, new AsyncCallback.ChildrenCallback() {
    //第二個起依次是：path、ctx、返回的子節(jié)點(diǎn)列表
    public void processResult(int i, String s, Object o, List<String> list) {
      System.out.println("子節(jié)點(diǎn)列表：" + list);
    }
  //ctx實(shí)參
  }, null);

//獲取節(jié)點(diǎn)數(shù)據(jù)，返回byte[]

  //同步方式
  byte[] data = null;
  try {
    //第二個參數(shù)是watch，第三個是stat
    data = zooKeeper.getData("/mall", false, null);
  } catch (KeeperException | InterruptedException e) {
    e.printStackTrace();
  }
  //調(diào)用new String()時要判斷data是否為null，如果是null會拋NPE
  if (data==null){
    System.out.println("該節(jié)點(diǎn)沒有數(shù)據(jù)");
  }
  else{
    System.out.println("節(jié)點(diǎn)數(shù)據(jù)："+new String(data));
  }


  //異步回調(diào)
  zooKeeper.getData("/mall", false, new AsyncCallback.DataCallback() {
    //第二個起依次是：path、ctx、返回的節(jié)點(diǎn)數(shù)據(jù)、節(jié)點(diǎn)狀態(tài)
    public void processResult(int i, String s, Object o, byte[] bytes, Stat stat) {
      //不必判斷bytes是否是null，如果節(jié)點(diǎn)沒有數(shù)據(jù)，不會調(diào)用回調(diào)函數(shù)；執(zhí)行到此，說明bytes不是null
      System.out.println("節(jié)點(diǎn)數(shù)據(jù)：" + new String(bytes) );
    }
    //ctx實(shí)參
  }, null);

//設(shè)置|更新節(jié)點(diǎn)據(jù)

  //同步方式
  try {
    //最后一個參數(shù)是版本號
    zooKeeper.setData("/mall", "1234".getBytes(), -1);
    System.out.println("設(shè)置節(jié)點(diǎn)數(shù)據(jù)成功");
  } catch (KeeperException | InterruptedException e) {
    System.out.println("設(shè)置節(jié)點(diǎn)數(shù)據(jù)失敗");
    e.printStackTrace();
  }


  //異步回調(diào)
  zooKeeper.setData("/mall", "1234".getBytes(), -1, new AsyncCallback.StatCallback() {
    //第二個是path，第三個是ctx
    public void processResult(int i, String s, Object o, Stat stat) {

    }
  // ctx
  },null);

//設(shè)置acl權(quán)限
    
  //第一個參數(shù)指定權(quán)限,第二個是Id對象
  ACL acl = new ACL(ZooDefs.Perms.ALL, new Id("auth", "chy:abcd"));
  
  List<ACL> aclList = new ArrayList<>();
  aclList.add(acl);
  
  //如果List中只有一個ACL對象，也可以這樣寫
  //List<ACL> aclList = Collections.singletonList(auth);
    
  //驗(yàn)證權(quán)限，需寫在設(shè)置權(quán)限之前。如果之前沒有設(shè)置權(quán)限，也需要先驗(yàn)證本次即將設(shè)置的用戶
  zooKeeper.addAuthInfo("digest","chy:abcd".getBytes());

  
  //方式一 setAcl
  try {
    //第二個參數(shù)是List<ACL>，第三個參數(shù)是版本號
    zooKeeper.setACL("/mall", aclList, -1);
    System.out.println("設(shè)置權(quán)限成功");
  } catch (KeeperException | InterruptedException e) {
    System.out.println("設(shè)置權(quán)限失敗");
    e.printStackTrace();
  }

  
  //方式二 在創(chuàng)建節(jié)點(diǎn)時設(shè)置權(quán)限
  try {
    zooKeeper.create("/mall","abcd".getBytes(),aclList,CreateMode.PERSISTENT);
    System.out.println("已創(chuàng)建節(jié)點(diǎn)并設(shè)置權(quán)限");
  } catch (KeeperException | InterruptedException e) {
    e.printStackTrace();
  }

//查看acl權(quán)限
    
  //設(shè)置權(quán)限之后，以后操作時需要先驗(yàn)證用戶，一次session中驗(yàn)證一次即可
  zooKeeper.addAuthInfo("digest","chy:abcd".getBytes());

  
  //同步方式
  try {
    List<ACL> aclList = zooKeeper.getACL("/mall", null);
    System.out.println("acl權(quán)限："+aclList);
  } catch (KeeperException | InterruptedException e) {
    System.out.println("獲取acl權(quán)限失敗");
    e.printStackTrace();
  }


  //異步回調(diào)
  zooKeeper.getACL("/mall3", null, new AsyncCallback.ACLCallback() {
    //第二個起：path、ctx、獲取到的List<ACL>、節(jié)點(diǎn)狀態(tài)
    public void processResult(int i, String s, Object o, List<ACL> list, Stat stat) {
      //就算沒有手動設(shè)置acl權(quán)限，默認(rèn)也是有值的
      System.out.println("acl權(quán)限："+list);
    }
  //ctx實(shí)參
  },null);

//添加監(jiān)聽 方式一
  try {
    CountDownLatch countDownLatch = new CountDownLatch(1);

    zooKeeper.getData("/mall", new Watcher() {
      public void process(WatchedEvent watchedEvent) {
        //watcher會監(jiān)聽該節(jié)點(diǎn)所有的事件，不管發(fā)生什么事件都會調(diào)用process()來處理，需要先判斷一下事件類型
        if (watchedEvent.getType().equals(Event.EventType.NodeDataChanged)){
          System.out.println("節(jié)點(diǎn)數(shù)據(jù)改變了");
          //會一直監(jiān)聽，如果只監(jiān)聽一次數(shù)據(jù)改變，將下面這句代碼取消注釋即可
          //countDownLatch.countDown();
        }
      }
    }, null);
    //默認(rèn)watcher是一次性的，如果要一直監(jiān)聽，需要借助CountDownLatch
    countDownLatch.await();
  } catch (KeeperException | InterruptedException e) {
    e.printStackTrace();
  }

//添加監(jiān)聽 方式二  
 　　try {
    CountDownLatch countDownLatch1 = new CountDownLatch(1);
    zooKeeper.addWatch("/mall", new Watcher() {
      @Override
      public void process(WatchedEvent watchedEvent) {
        if (watchedEvent.getType().equals(Event.EventType.NodeDataChanged)){
          System.out.println("節(jié)點(diǎn)數(shù)據(jù)改變了");
          //如果只監(jiān)聽一次數(shù)據(jù)改變，將下面這句代碼注釋掉
          //countDownLatch1.countDown();
        }
      }
    //監(jiān)聽模式，PERSISTENT是不監(jiān)聽子孫節(jié)點(diǎn)，PERSISTENT_RECURSIVE是遞歸監(jiān)聽子孫節(jié)點(diǎn)
    }, AddWatchMode.PERSISTENT_RECURSIVE);
    countDownLatch1.await();
  } catch (KeeperException | InterruptedException e) {
    e.printStackTrace();
  }

//移除監(jiān)聽 方式一
  try {
    zooKeeper.addWatch("/mall",null,AddWatchMode.PERSISTENT);
    System.out.println("已移除監(jiān)聽");
  } catch (KeeperException | InterruptedException e) {
    e.printStackTrace();
  }

//移除監(jiān)聽 方式二
  try {
    //第二個參數(shù)是Watcher，原來添加的那個Watcher監(jiān)聽對象，不能是null
    //第三個參數(shù)指定要移除監(jiān)聽的哪部分，Any是移除整個監(jiān)聽，Data是移除對數(shù)據(jù)的監(jiān)聽，Children是移除對子節(jié)點(diǎn)的遞歸監(jiān)聽
    //最后一個參數(shù)指定未連接到zkServe時，是否移除本地監(jiān)聽部分
    zooKeeper.removeWatches("/mall",watcher, Watcher.WatcherType.Children,true);
  } catch (InterruptedException | KeeperException e) {
    e.printStackTrace();
  }