这里的创建zk客户端采用的是一个叫Curator的工具包，建议后面可以研究下，并将这个工具包封装为自己的

    1. public CuratorZookeeperClient(URL url) {
    2.     super(url);
    3.     try {
    4.         int timeout = url.getParameter(Constants.TIMEOUT_KEY, 5000);
    5.         CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder()
    6.             .connectString(url.getBackupAddress())
    7.             .retryPolicy(new RetryNTimes(1, 1000))
    8.             .connectionTimeoutMs(timeout);
    9.         String authority = url.getAuthority();
    10.         if (authority != null && authority.length() > 0) {
    11.             builder = builder.authorization("digest", authority.getBytes());
    12.         }
    13.         client = builder.build();
    14.         client.getConnectionStateListenable().addListener(new ConnectionStateListener() {
    15.             @Override
    16.             public void stateChanged(CuratorFramework client, ConnectionState state) {
    17.                 if (state == ConnectionState.LOST) {
    18.                     CuratorZookeeperClient.this.stateChanged(StateListener.DISCONNECTED);
    19.                 } else if (state == ConnectionState.CONNECTED) {
    20.                     CuratorZookeeperClient.this.stateChanged(StateListener.CONNECTED);
    21.                 } else if (state == ConnectionState.RECONNECTED) {
    22.                     CuratorZookeeperClient.this.stateChanged(StateListener.RECONNECTED);
    23.                 }
    24.             }
    25.         });
    26.         client.start();
    27.     } catch (Exception e) {
    28.         throw new IllegalStateException(e.getMessage(), e);
    29.     }
    30. }