zookeeper Zookeeper

这是ZooKeeper客户端库的主要类。使用一个ZooKeeper服务，应用程序必须首先实例化ZooKeeper类的对象。所有的迭代都将通过调用ZooKeeper类的方法来完成。除非另有说明，该类的方法是线程安全的。

构造函数：

    public ZooKeeper(String connectString, int sessionTimeout, Watcher watcher)
        throws IOException
    {
        this(connectString, sessionTimeout, watcher, false);
    }

　　

    public ZooKeeper(String connectString, int sessionTimeout, Watcher watcher,
            boolean canBeReadOnly)
        throws IOException{
        LOG.info("Initiating client connection, connectString=" + connectString
                + " sessionTimeout=" + sessionTimeout + " watcher=" + watcher);

        watchManager.defaultWatcher = watcher;

        ConnectStringParser connectStringParser = new ConnectStringParser(
                connectString);
        HostProvider hostProvider = new StaticHostProvider(
                connectStringParser.getServerAddresses());
        cnxn = new ClientCnxn(connectStringParser.getChrootPath(),
                hostProvider, sessionTimeout, this, watchManager,
                getClientCnxnSocket(), canBeReadOnly);
        cnxn.start();
    }

　　

    public ZooKeeper(String connectString, int sessionTimeout, Watcher watcher,
            long sessionId, byte[] sessionPasswd)
        throws IOException{
        this(connectString, sessionTimeout, watcher, sessionId, sessionPasswd, false);
    }

　　

    public ZooKeeper(String connectString, int sessionTimeout, Watcher watcher,
            long sessionId, byte[] sessionPasswd, boolean canBeReadOnly)
        throws IOException{
        LOG.info("Initiating client connection, connectString=" + connectString
                + " sessionTimeout=" + sessionTimeout
                + " watcher=" + watcher
                + " sessionId=" + Long.toHexString(sessionId)
                + " sessionPasswd="
                + (sessionPasswd == null ? "<null>" : "<hidden>"));

        watchManager.defaultWatcher = watcher;

        ConnectStringParser connectStringParser = new ConnectStringParser(
                connectString);
        HostProvider hostProvider = new StaticHostProvider(
                connectStringParser.getServerAddresses());
        cnxn = new ClientCnxn(connectStringParser.getChrootPath(),
                hostProvider, sessionTimeout, this, watchManager,
                getClientCnxnSocket(), sessionId, sessionPasswd, canBeReadOnly);
        cnxn.seenRwServerBefore = true; // since user has provided sessionId
        cnxn.start();
    }