curator分布式序号生成器

1、前提在zookeeper上先创建好锁目录

2、如下代码使用curator提供的分布式锁来试下序号自增，这里没有考虑数据的上界，只是个样例：

package mytest;import java.util.concurrent.BrokenBarrierException;import java.util.concurrent.CyclicBarrier;import org.apache.curator.framework.CuratorFramework;import org.apache.curator.framework.CuratorFrameworkFactory;import org.apache.curator.framework.recipes.locks.InterProcessMutex;import org.apache.curator.retry.ExponentialBackoffRetry;/** * distributed sequential number generator based on zookeeper * prediction: zookeeper has the lock path already. this program just watch that path * @author sing * */public class DistrSeqGen {private CuratorFramework curator;private InterProcessMutex mutex ;private String lockPath;private DistrSeqGen(String serverLoc,String lockPath) {//synchronized(DistrSeqGen.class) { curator = CuratorFrameworkFactory.builder().connectString(serverLoc).retryPolicy(new ExponentialBackoffRetry(1000,2)).build(); curator.start(); this.lockPath = lockPath;// curator.usingNamespace(lockPath); mutex = new InterProcessMutex(curator, lockPath);//create the node automatically//}}/** * get next sequetial number  * @return * @throws Exception  */public int next() throws Exception{int seq =0;try {mutex.acquire();byte[] seqInByte = curator.getData().forPath(this.lockPath); seq= Integer.parseInt(new String(seqInByte));seq++;curator.setData().forPath(lockPath,new Integer(seq).toString().getBytes());}catch(Exception e) {e.printStackTrace();}finally {mutex.release();}return seq;}public static class ClientRunnable implements Runnable{private static final CyclicBarrier barrier = new CyclicBarrier(5);boolean interrupted =false;public void run() {while(!interrupted) {DistrSeqGen gen = new DistrSeqGen("localhost:2181","/DistrLock");try {barrier.await();System.out.println(Thread.currentThread().getName() + ":" + gen.next());} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (BrokenBarrierException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}if(Thread.currentThread().isInterrupted()) {interrupted = true;}}}}public static void main(String[] args) {// TODO Auto-generated method stubnew Thread(new ClientRunnable()).start();new Thread(new ClientRunnable()).start();new Thread(new ClientRunnable()).start();new Thread(new ClientRunnable()).start();new Thread(new ClientRunnable()).start();}}

3、自测代码有个问题，每次获取了119个序号之后，就会无法再次获取到锁，然后就会失去zookeeper的链接。自测环境是本地zookeeper服务器，没有集群。