Java调用Zookeeper的实现步骤

public ZooKeeper(String connectString, int sessionTimeout, Watcher watcher) throws IOException


public String create(String path, byte[] data, List<ACL> acl, CreateMode createMode) throws KeeperException, InterruptedException


public List<String> getChildren(String path, boolean watch) throws KeeperException, InterruptedException


public byte[] getData(String path, Watcher watcher, Stat stat) throws KeeperException, InterruptedException


public void getData(String path, boolean watch, AsyncCallback.DataCallback cb, Object ctx)


public Stat setData(String path, byte[] data, int version) throws KeeperException, InterruptedException


public Stat exists(String path, boolean watch) throws KeeperException, InterruptedException


public void delete(String path, int version) throws InterruptedException, KeeperException

try {
  ZooKeeper　zooKeeper = new ZooKeeper("172.23.34.13:2181", 15000, event -> {
        if (event.getType() == Watcher.Event.EventType.None && event.getState() == Watcher.Event.KeeperState.SyncConnected) {
            System.out.println("Connectted successful.");
        }
    });
} catch (IOException e) {
    e.printStackTrace();
}

@Test
public void create() throws KeeperException, InterruptedException {
    //参数：1，节点路径； 2，要存储的数据； 3，节点的权限； 4，节点的类型
    String nodePath = zooKeeper.create("/java/2183", "This is Java Node 2183.".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    System.out.println(nodePath);
}

public void getChildren() throws KeeperException, InterruptedException {
    List<String> children = zooKeeper.getChildren("/", true);
    for (String child : children) {
        System.out.println("child: "+child);
    }
}

@Test
public void getData() throws KeeperException, InterruptedException {
    String path = "/java";
    byte[] bytes = zooKeeper.getData(path, event -> {
        if (event.getType() == Watcher.Event.EventType.NodeDataChanged && path.equals(event.getPath())) {
            System.out.println("Date changed.");
        }
    }, null);
    System.out.printf("The data of %s is : %s \n",path, new String(bytes));
}

@Test
public void getDataAsync() {
    String path = "/java";
    zooKeeper.getData(path, false, new AsyncCallback.DataCallback() {
        @Override
        public void processResult(int i, String s, Object o, byte[] bytes, Stat stat) {
            System.out.printf("The data of %s is : %s \n",path, new String(bytes));
        }
    },"1000");

    //休眠20秒，查看响应结果
    try {
        Thread.sleep(20000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

@Test
public void setData() throws KeeperException, InterruptedException {
    Stat stat = zooKeeper.setData("/java", "This is from java.".getBytes(), -1);
    //更新节点后，version会自动+1。故，返回值为0
    System.out.println(stat.getAversion());
}

@Test
public void setDataThread() throws KeeperException, InterruptedException {
    String path = "/java";
    Stat stat = new Stat();
    //1,先获取节点的当前版本
    zooKeeper.getData(path,false,stat);
    //2，在当前版本的基础上修改节点内容
    zooKeeper.setData(path, "This is from java.".getBytes(), stat.getVersion());
}

@Test
public void exists() throws KeeperException, InterruptedException {
    Stat stat = zooKeeper.exists("/java", false);
    if (stat == null) {
        System.out.println("Not Exists.");
    }else {
        System.out.println("Exists.");
    }
}

@Test
public void delete() throws KeeperException, InterruptedException {
    //version = -1 : 匹配所有的版本
    zooKeeper.delete("/java/2182", -1);
}