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 block
e.printStackTrace();
} catch (BrokenBarrierException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

if(Thread.currentThread().isInterrupted()) {
interrupted = true;
}
}
}
}

public static void main(String[] args) {
// TODO Auto-generated method stub
new 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。