ZooKeeper建立会话

来源：互联网发布：mysql 字段原子累加编辑：程序博客网时间：2024/05/16 07:07

ZooKeeper万事的开始建立会话

由于ZooKeeper客户端和服务端建立会话是一个异步过程，所以在建立会话时需要用到ZooKeeper监听机制即“org.apache.zookeeper.Watcher”接口，和“java.util.concurrent.CountDownLatch”类，控制阻塞和同步，对于CountDownLatch不了解的看官可以百度一下啦。

package zkapitest;import java.io.IOException;import java.util.concurrent.CountDownLatch;import org.apache.zookeeper.WatchedEvent;import org.apache.zookeeper.Watcher;import org.apache.zookeeper.Watcher.Event.EventType;import org.apache.zookeeper.Watcher.Event.KeeperState;import org.apache.zookeeper.ZooKeeper;public class CreateSession {public static void main(String[] args) {try {ZooKeeper zookeeper = new ZKClient().getZooKeeper();System.out.println(zookeeper.getSessionId());} catch (IOException e) {e.printStackTrace();} catch (InterruptedException e) {e.printStackTrace();}}}/** * ZooKeeper工具类 实现Watcher接口 * * @CreateTime 2016-1-25下午8:25:39 * * @Vsersion 1.0 */class ZKClient implements Watcher {private CountDownLatch connectedSemaphore = new CountDownLatch(1);//定义阻塞线程,计数器为1private ZooKeeper zookeeper = null;private static String URL = "192.168.0.203:2181";//服务地址public ZooKeeper getZooKeeper() throws IOException, InterruptedException{zookeeper = new ZooKeeper(URL, 5000, this);connectedSemaphore.await();//线程阻塞return zookeeper;}public ZooKeeper getZooKeeper(long sessionId, byte[] sessionPW) throws IOException, InterruptedException{zookeeper = new ZooKeeper(URL, 5000, this, sessionId, sessionPW);connectedSemaphore.await();//线程阻塞return zookeeper;}@Overridepublic void process(WatchedEvent event) {if (KeeperState.SyncConnected == event.getState()) {if(event.getType() == EventType.None && null == event.getPath()){connectedSemaphore.countDown();//释放线程、技术减一}} }}

0 0