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Zookeeper_2_Watcher.java
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Zookeeper_2_Watcher.java
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package zookeeper.zookeeper;
import java.io.IOException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
/**
* Zookeepr实现分布式锁
*/
public class Zookeeper_2_Watcher {
private String zkconfig = "192.168.1.207:2181";
private static String lockNameSpace = "/mylock";
private String nodeString = lockNameSpace + "/lock1";
private static ZooKeeper zk;
public Zookeeper_2_Watcher() {
try {
zk = new ZooKeeper(zkconfig, 6000, new Watcher() {
@Override
public void process(WatchedEvent watchedEvent) {
System.out.println("Receive event " + watchedEvent);
if (Event.KeeperState.SyncConnected == watchedEvent.getState()) {
System.out.println("connection is ok");
}
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
private void watchNode(String nodeString, final Thread thread) throws InterruptedException {
try {
zk.exists(nodeString, new Watcher() {
@Override
public void process(WatchedEvent watchedEvent) {
System.out.println("==" + watchedEvent.toString());
if (watchedEvent.getType() == Event.EventType.NodeDeleted) {
System.out.println("Threre is a Thread released Lock==============");
thread.interrupt();
}
}
});
} catch (KeeperException e) {
e.printStackTrace();
}
}
/**
* 获取锁
*
* @return
* @throws InterruptedException
*/
public boolean lock() throws Exception {
String path = null;
while (true) {
CountDownLatch countDownLatch = new CountDownLatch(1);
try {
path = zk.create(nodeString, "".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
} catch (KeeperException e) {
System.out.println(Thread.currentThread().getName() + " 请求失败");
try {
zk.exists(nodeString, new Watcher() {
@Override
public void process(WatchedEvent watchedEvent) {
System.out.println("事件来了：" + watchedEvent.toString());
if (watchedEvent.getType() == Event.EventType.NodeDeleted) {
System.out.println("delete事件");
countDownLatch.countDown();
}
}
});
} catch (KeeperException e1) {
e.printStackTrace();
}
}
if (path != null && !path.isEmpty()) {
System.out.println(Thread.currentThread().getName() + " 拿到 Lock...");
break;
}
countDownLatch.await();
}
return true;
}
/**
* 释放锁
*/
public void unlock() {
try {
zk.delete(nodeString, -1);
System.out.println(Thread.currentThread().getName() + "释放 Lock...");
} catch (InterruptedException e) {
e.printStackTrace();
} catch (KeeperException e) {
e.printStackTrace();
}
}
public static void main(String args[]) throws InterruptedException {
Zookeeper_2_Watcher test = new Zookeeper_2_Watcher();
try {
Thread.sleep(100);
zk.create(lockNameSpace, "".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
} catch (KeeperException e) {
} catch (InterruptedException e) {
}
ExecutorService service = Executors.newFixedThreadPool(10);
for (int i = 0; i < 4; i++) {
service.execute(() -> {
try {
test.lock();
Thread.sleep(1000);
} catch (Exception e) {
e.printStackTrace();
}
test.unlock();
});
}
service.shutdown();
}
}