java 操作 zookeeper API

/** * ZooKeeper Java Api 使用样例<br>  * * @author <a href="mailto:[e-mail]">East271536394</a> * @version 2013-6-20 下午12:39:41 */import java.io.IOException;import java.util.concurrent.CountDownLatch;import org.apache.zookeeper.CreateMode;import org.apache.zookeeper.KeeperException;import org.apache.zookeeper.WatchedEvent;import org.apache.zookeeper.Watcher;import org.apache.zookeeper.Watcher.Event.KeeperState;import org.apache.zookeeper.ZooDefs.Ids;import org.apache.zookeeper.ZooKeeper;public class JavaApiSample implements Watcher {private static final int SESSION_TIMEOUT = 10000;private static final String CONNECTION_STRING = "202.173.8.57:4181,202.173.8.58:4181,202.173.8.59:4181";private static final String ZK_PATH = "/knet";private ZooKeeper zk = null;private CountDownLatch connectedSemaphore = new CountDownLatch(1);private boolean init = false;/**  * 创建ZK连接  * @param connectString  ZK服务器地址列表  * @param sessionTimeout   Session超时时间  */public void createConnection(String connectString, int sessionTimeout) {this.releaseConnection();try {zk = new ZooKeeper(connectString, sessionTimeout, this);init = true;connectedSemaphore.await();init = false;} catch (InterruptedException e) {System.out.println("连接创建失败，发生 InterruptedException");e.printStackTrace();} catch (IOException e) {System.out.println("连接创建失败，发生 IOException");e.printStackTrace();}}/**  * 关闭ZK连接  */public void releaseConnection() {if (this.zk != null) {try {this.zk.close();} catch (InterruptedException e) {// ignore e.printStackTrace();}}}/**  *  创建节点  * @param path 节点path  * @param data 初始数据内容  * @return  */public boolean createPath(String path, String data) {try {System.out.println("节点创建成功, Path: " + this.zk.create(path, // data.getBytes(), // Ids.OPEN_ACL_UNSAFE, // CreateMode.EPHEMERAL) + ", content: " + data);} catch (KeeperException e) {System.out.println("节点创建失败，发生KeeperException");e.printStackTrace();} catch (InterruptedException e) {System.out.println("节点创建失败，发生 InterruptedException");e.printStackTrace();}return true;}/**  * 读取指定节点数据内容  * @param path 节点path  * @return  */public String readData(String path) {try {System.out.println("获取数据成功，path：" + path);return new String(this.zk.getData(path, true, null));} catch (KeeperException e) {System.out.println("读取数据失败，发生KeeperException，path: " + path);e.printStackTrace();return "";} catch (InterruptedException e) {System.out.println("读取数据失败，发生 InterruptedException，path: " + path);e.printStackTrace();return "";}}/**  * 更新指定节点数据内容  * @param path 节点path  * @param data  数据内容  * @return  */public boolean writeData(String path, String data) {try {System.out.println("更新数据成功，path：" + path + ", stat: " + this.zk.setData(path, data.getBytes(), -1));} catch (KeeperException e) {System.out.println("更新数据失败，发生KeeperException，path: " + path);e.printStackTrace();} catch (InterruptedException e) {System.out.println("更新数据失败，发生 InterruptedException，path: " + path);e.printStackTrace();}return false;}/**  * 删除指定节点  * @param path 节点path  */public void deleteNode(String path) {try {this.zk.delete(path, -1);System.out.println("删除节点成功，path：" + path);} catch (KeeperException e) {System.out.println("删除节点失败，发生KeeperException，path: " + path);e.printStackTrace();} catch (InterruptedException e) {System.out.println("删除节点失败，发生 InterruptedException，path: " + path);e.printStackTrace();}}public static void main(String[] args) {JavaApiSample sample = new JavaApiSample();sample.createConnection(CONNECTION_STRING, SESSION_TIMEOUT);if (sample.createPath(ZK_PATH, "我是节点初始内容")) {System.out.println();System.out.println("数据内容: " + sample.readData(ZK_PATH) + "\n");sample.writeData(ZK_PATH, "更新后的数据");System.out.println("数据内容: " + sample.readData(ZK_PATH) + "\n");sample.deleteNode(ZK_PATH);}sample.releaseConnection();}/**  * 收到来自Server的Watcher通知后的处理。  */@Overridepublic void process(WatchedEvent event) {System.out.println("收到事件通知：" + event.getState() + ",type :" + event.getType() + ",path :" + event.getPath()+ "\n");if (KeeperState.SyncConnected == event.getState()) {if (init) {System.out.println("connectedSemaphore.countDown()>>>>>>>>>>>>>>>>");connectedSemaphore.countDown();}}}}

运行结果如下:

收到事件通知：SyncConnected,type :None,path :nullconnectedSemaphore.countDown()>>>>>>>>>>>>>>>>节点创建成功, Path: /knet, content: 我是节点初始内容获取数据成功，path：/knet数据内容: 我是节点初始内容收到事件通知：SyncConnected,type :NodeDataChanged,path :/knet更新数据成功，path：/knet, stat: 30064771186,30064771187,1371704002257,1371704002267,1,0,0,89895709067640842,18,0,30064771186获取数据成功，path：/knet数据内容: 更新后的数据收到事件通知：SyncConnected,type :NodeDeleted,path :/knet删除节点成功，path：/knet2013-06-20 12:53:18,835 [myid:] - INFO  [main:ZooKeeper@679] - Session: 0x13f5fabcdcf000a closed2013-06-20 12:53:18,835 [myid:] - INFO  [main-EventThread:ClientCnxn$EventThread@511] - EventThread shut down