zk实现分布式锁
基于curator
基于curator实现的分布式锁主要有三种：
1.基于InterProcessMutex实现的分布式锁属于可重入式锁，当一个客户端获取到lock锁之后，可以重复调用acquire()而不会发生阻塞。
2.基于InterProcessSemaphoreMutex实现的分布式的分布式锁是不可重入的，当一个客户端获取到lock锁之后，再次调用acquire方法获取锁时会发生阻塞。
3.基于InterProcessReadWriteLock实现的分布式锁里边包含了读锁与写锁，其中读锁与读锁互斥，读锁与写锁互斥，读锁与读锁不互斥。
可重入锁：
package com.topsec.lock;
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;
/**
* 测试可重入锁（可以多次获得锁不会被阻塞，释放时也需释放多把锁）
* @author 76524
*
*/
public class SharedReentrantLock1 implements Runnable{
private InterProcessMutex lock;//可重入锁实现类
private String lockPAth = "/lock/shareLock";
private int i;
private String clientName;
//zookeeper集群地址
public static final String ZOOKEEPERSTRING = "192.168.99.12 9:2181,192.168.99.153:2181,192.168.99.171:2181";
public SharedReentrantLock1(CuratorFramework client,String clientName) {
lock = new InterProcessMutex(client, lockPAth);
this.clientName = clientName;
}
public void run() {
try {
Thread.sleep((new java.util.Random().nextInt(2000)));
lock.acquire(); //增加第一把锁
if(lock.isAcquiredInThisProcess()) {
System.out.println(clientName + " 获得锁");
i++;
}
lock.acquire(); //增加第二把锁
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
System.out.println(clientName+"释放第一把锁");
lock.release();
System.out.println(clientName+"释放第二把锁");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static void main(String[] args) {
CuratorFramework client = CuratorFrameworkFactory.newClient(ZOOKEEPERSTRING, new ExponentialBackoffRetry(1000, 3));
client.start();
//启动100个线程进行测试
for(int i = 0;i<100;i++) {
SharedReentrantLock1 sharedReentrantLock = new SharedReentrantLock1(client, "第"+i+"个客户端：");
Thread thread = new Thread(sharedReentrantLock);
thread.start();
}
}
}
不可重入锁：
package com.topsec.lock;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.locks.InterProcessSemaphoreMutex;
import org.apache.curator.retry.ExponentialBackoffRetry;
/**
* 测试不可重入锁（只能获得一次锁，使用完后释放）
* @author 76524
*
*/
public class SharedNOReentrantLock implements Runnable{
private InterProcessSemaphoreMutex lock;//不可重入锁
private String lockPAth = "/lock/shareLock";
private int i;
private String clientName;
//zookeeper集群地址
public static final String ZOOKEEPERSTRING = "192.168.99.129:2181,192.168.99.153:2181,192.168.99.171:2181";
public SharedNOReentrantLock(CuratorFramework client,String clientName) {
lock = new InterProcessSemaphoreMutex(client, lockPAth);
this.clientName = clientName;
}
public void run() {
try {
Thread.sleep((new java.util.Random().nextInt(2000)));
lock.acquire(); //增加第一把锁
if(lock.isAcquiredInThisProcess()) {
System.out.println(clientName + " 获得锁");
i++;
}
lock.acquire(); //增加第二把锁这个锁相当于不起作用
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
// lock.release();
System.out.println(clientName+"释放第一把锁");
lock.release();
System.out.println(clientName+"释放第二把锁");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static void main(String[] args) {
CuratorFramework client =
CuratorFrameworkFactory.newClient(ZOOKEEPERSTRING, new ExponentialBackoffRetry(1000, 3));
client.start();
for(int i = 0;i<100;i++) {
SharedReentrantLock2 sharedReentrantLock = new SharedReentrantLock2(client, "第"+i+"个客户端：");
Thread thread = new Thread(sharedReentrantLock);
thread.start();
}
}
}
参考文章： https://blog.csdn.net/pengshuai128/article/details/70593995 https://www.cnblogs.com/zhangjunqing/p/7823626.html