分布式锁-基于zookeeper客户端curator实现锁机制（一）锁基础

分布式锁基础：继承接口的锁实现，以统一的接口调用完成，封装错误处理

定义接口，实现此接口都拥有获取锁与释放锁

/*
* Copyright 2016-2018. Individual ownership panw
*
* Tech blog at http://blog.csdn.net/hatsune_miku_. *
* Contact Mailbox at <a href="mailto:mikuismywifu@gmail.com">panw</a>.
*
*/
package com.miku.common.util.lock;

import org.apache.curator.framework.recipes.locks.InterProcessLock;

/**
* @author:panw.
* @date:2018/1/16.
*/
public interface Lock {

/**
* 获取锁 - 根据接口子类推断出当前锁类型
*
* @see org.apache.curator.framework.recipes.locks.InterProcessMultiLock
* @see org.apache.curator.framework.recipes.locks.InterProcessMutex
* @see org.apache.curator.framework.recipes.locks.InterProcessSemaphoreMutex
* @param interProcessLock
* @throws Exception
*/
void lock(InterProcessLock interProcessLock) throws Exception;

/**
* 获取锁 - 阻止直到可用或给定的时间到期
*
* @param interProcessLock
* @param milliseconds
* @throws Exception
*/
boolean lock(InterProcessLock interProcessLock,long milliseconds) throws Exception;

/**
* 释放锁 - 根据锁接口子类推断出当前锁类型
*
* @see org.apache.curator.framework.recipes.locks.InterProcessMultiLock
* @see org.apache.curator.framework.recipes.locks.InterProcessMutex
* @see org.apache.curator.framework.recipes.locks.InterProcessSemaphoreMutex
* @param interProcessLock
* @throws Exception
*/
void unlock(InterProcessLock interProcessLock) throws Exception;
}

锁抽象，获取zk上下文锁地址，zk链接地址，监听zk链接状态

/*
* Copyright 2016-2018. Individual ownership panw
*
* Tech blog at http://blog.csdn.net/hatsune_miku_. *
* Contact Mailbox at <a href="mailto:mikuismywifu@gmail.com">panw</a>.
*
*/
package com.miku.common.util.lock.support;

import com.miku.common.util.lock.Lock;
import com.miku.common.utils.spring.SpringUtils;
import com.miku.common.zookeeper.ZookeeperClient;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.locks.InterProcessLock;
import org.apache.curator.framework.state.ConnectionState;
import org.apache.curator.framework.state.ConnectionStateListener;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;

/**
* zookeeper分布式锁实现,所有获取锁都是公平锁的实现
*
* @see org.apache.curator.framework.recipes.locks
*
* @author:panw.
* @date:2018/1/17.
*/
public abstract class AbstractZookeeperLock<E extends InterProcessLock>  implements Lock{

public static CuratorFramework curatorFramework;
public final ConcurrentHashMap<String,E> locks = new ConcurrentHashMap<>();

public AbstractZookeeperLock(){
ZookeeperClient zookeeperClient = SpringUtils.getBean(ZookeeperClient.class);
curatorFramework = zookeeperClient.getClient();
}

@Override
public void lock(InterProcessLock interProcessLock) throws Exception{
try {
interProcessLock.acquire();
lockConnectionStateListenable();
} catch (Exception e) {
throw new IllegalStateException("锁丢失=>" + e);
}
}

@Override
public boolean lock(InterProcessLock interProcessLock,long time) throws Exception{
boolean state;
try {
state = interProcessLock.acquire(time, TimeUnit.MILLISECONDS);
lockConnectionStateListenable();
} catch (Exception e) {
throw new IllegalStateException("锁丢失=>" + e);
}
return state;
}

@Override
public void unlock(InterProcessLock interProcessLock) throws Exception{
try {
interProcessLock.release();
} catch (Exception e) {
throw new IllegalStateException("锁丢失=>" + e);
}
}

/**
* 监听zk连接状态.
*/
public void lockConnectionStateListenable() throws Exception{
curatorFramework.getConnectionStateListenable().addListener(new ConnectionStateListener() {
@Override
// ConnectionStateListener并监视SUSPENDED和LOST状态更改。如果报告“挂起”状态，则不能确定是否仍然保持锁定状态，
// 除非您随后收到“重新连接”状态。如果报告失去状态，则确定您不再持有该锁
public void stateChanged(CuratorFramework client, ConnectionState state) {
if (state == ConnectionState.LOST) {
// TODO 考虑删除锁实例
throw new IllegalStateException("会话超时锁丢失=>");
}
}
});
}
}

<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-framework</artifactId>
<version>${curator_version}</version>
</dependency>

<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-recipes</artifactId>
<version>${curator_version}</version>
</dependency>