基于redis集群实现的分布式锁，可用于秒杀商品的库存数量管理，有測试代码(何志雄)

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在分布式系统中，常常会出现须要竞争同一资源的情况，本代码基于redis3.0.1+jedis2.7.1实现了分布式锁。

redis集群的搭建，请见我的另外一篇文章：<>《redis3.0.1集群环境搭建》

可用于比如秒杀系统中的商品库存的管理。付完整代码及測试用例。

package com.gaojiasoft.gaojiaRedis;

import java.util.UUID;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import javax.annotation.PostConstruct;

import org.apache.commons.lang3.RandomUtils;
import org.apache.commons.lang3.concurrent.BasicThreadFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;

import redis.clients.jedis.JedisCluster;
import redis.clients.jedis.exceptions.JedisConnectionException;

/**
 * 分布式锁管理器，支持对单个资源加锁解锁。或给一批资源的批量加锁及解锁
* @ClassName: DistributedLockManger 
* @Description:  
* @author 何志雄 001
* @company 南京高嘉软件技术有限公司
* @date 2015年6月3日 下午5:44:06
 */
public class DistributedLockManger
{

    private static final Logger LOGGER = LoggerFactory.getLogger(DistributedLockManger.class);

    private static final int DEFAULT_SINGLE_EXPIRE_TIME = 3;

    //    private static final int DEFAULT_BATCH_EXPIRE_TIME = 6;

    //static的变量无法注解
    @Autowired
    JedisCluster jc;

    private static DistributedLockManger lockManger;

    public DistributedLockManger()
    {
    }

    @PostConstruct
    public void init()
    {
        lockManger = this;
        lockManger.jc = this.jc;
    }

    /**
     * 获取锁 假设锁可用   马上返回true。  否则马上返回false，作为非堵塞式锁使用 
     * @param key
     * @param value
     * @return
     */
    public static boolean tryLock(String key , String value)
    {
        try
        {
            return tryLock(key, value, 0L, null);
        }
        catch (InterruptedException e)
        {
            e.printStackTrace();
        }
        return false;
    }

    /**
     * 锁在给定的等待时间内空暇，则获取锁成功 返回true， 否则返回false。作为堵塞式锁使用
     * @param key 锁键
     * @param value 被谁锁定
     * @param timeout 尝试获取锁时长。建议传递500,结合实践单位。则可表示500毫秒
     * @param unit。建议传递TimeUnit.MILLISECONDS
     * @return
     * @throws InterruptedException 
     */
    public static boolean tryLock(String key , String value , long timeout , TimeUnit unit) throws InterruptedException
    {
        //纳秒
        long begin = System.nanoTime();
        do
        {
            //LOGGER.debug("{}尝试获得{}的锁.", value, key);
            Long i = lockManger.jc.setnx(key, value);
            if (i == 1)
            {
                lockManger.jc.expire(key, DEFAULT_SINGLE_EXPIRE_TIME);
                LOGGER.debug("{}成功获取{}的锁,设置锁过期时间为{}秒 ", value, key, DEFAULT_SINGLE_EXPIRE_TIME);
                return true;
            }
            else
            {
                // 存在锁 ，但可能获取不到，原因是获取的一刹那间
//                String desc = lockManger.jc.get(key);
//                LOGGER.error("{}正被{}锁定.", key, desc);
            }
            if (timeout == 0)
            {
                break;
            }
            //在其睡眠的期间，锁可能被解，也可能又被他人占用，但会尝试继续获取锁直到指定的时间
            Thread.sleep(100);
        }
        while ((System.nanoTime() - begin) < unit.toNanos(timeout));
        //因超时没有获得锁
        return false;
    }

    /**
     * 释放单个锁
     * @param key 锁键
     * @param value 被谁释放
     */
    public static void unLock(String key , String value)
    {
        try
        {
            lockManger.jc.del(key);
            LOGGER.debug("{}锁被{}释放 .", key, value);
        }
        catch (JedisConnectionException je)
        {

        }
        catch (Exception e)
        {

        }
    }

public void test() throws InterruptedException
    {
        String productId = "18061249844";
        String userId;
        for (int i = 1; i <= 500; i++)
        {
            //随机产生一个用户
            userId = UUID.randomUUID().toString();
            //该用户试图锁定(假设被锁，尝试等待300毫秒)。在处理一些事情后。再释放锁
            testLock(productId, userId);
            Thread.sleep(20);
        }
    }

    private static final ThreadPoolExecutor executor = new ThreadPoolExecutor(150, 150, 30L, TimeUnit.SECONDS,
            new LinkedBlockingQueue<Runnable>(), new BasicThreadFactory.Builder().daemon(true)
                    .namingPattern("mongo-oper-%d").build(), new ThreadPoolExecutor.CallerRunsPolicy());

    private static void testLock(final String key , final String value)
    {
        executor.execute(new Runnable()
        {
            @Override
            public void run()
            {
                try
                {
                    //获取锁，假设不能马上获取，尝试等待1000毫秒
                    boolean isLock = DistributedLockManger.tryLock(key, value, 500, TimeUnit.MILLISECONDS);
                    if (isLock)
                    {
                        //doSomething(占用锁20毫秒到4秒，模拟处理事务)
                        long doSomeThingTime = RandomUtils.nextLong(20, 4000);
                        LOGGER.debug("{}将持有锁{}时长{}毫秒.", value, key, doSomeThingTime);
                        Thread.sleep(doSomeThingTime);
                        //然后释放锁
                        DistributedLockManger.unLock(key, value);
                    }
                }
                catch (Throwable th)
                {
                }
            }
        });
    }

    public JedisCluster getJc()
    {
        return jc;
    }

    public void setJc(JedisCluster jc)
    {
        this.jc = jc;
    }
}

Spring配置：

redis.properties

#最大闲置连接数
im.hs.server.redis.maxIdle=500
#最大连接数，超过此连接时操作redis会报错
im.hs.server.redis.maxTotal=5000
im.hs.server.redis.maxWaitTime=1000
im.hs.server.redis.testOnBorrow=true
#最小闲置连接数，spring启动的时候自己主动建立该数目的连接供应用程序使用，不够的时候会申请。
im.hs.server.redis.minIdle=300

spring-redis.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="
			http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
			http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

	<context:property-placeholder location="classpath:conf/redis/redis.properties" />

	<!-- 其实，仅仅须要连接1个节点就能够 -->
	<bean id="culster7001" class="redis.clients.jedis.HostAndPort">
		<constructor-arg name="host" value="192.168.62.153" />
		<constructor-arg name="port" value="7001" />
	</bean>
	<bean id="culster7002" class="redis.clients.jedis.HostAndPort">
		<constructor-arg name="host" value="192.168.62.153" />
		<constructor-arg name="port" value="7002" />
	</bean>
	<bean id="culster7003" class="redis.clients.jedis.HostAndPort">
		<constructor-arg name="host" value="192.168.62.154" />
		<constructor-arg name="port" value="7003" />
	</bean>
	<bean id="culster7004" class="redis.clients.jedis.HostAndPort">
		<constructor-arg name="host" value="192.168.62.154" />
		<constructor-arg name="port" value="7004" />
	</bean>
	<bean id="culster7005" class="redis.clients.jedis.HostAndPort">
		<constructor-arg name="host" value="192.168.62.155" />
		<constructor-arg name="port" value="7005" />
	</bean>
	<bean id="culster7006" class="redis.clients.jedis.HostAndPort">
		<constructor-arg name="host" value="192.168.62.155" />
		<constructor-arg name="port" value="7006" />
	</bean>
	<bean id="culster7007" class="redis.clients.jedis.HostAndPort">
		<constructor-arg name="host" value="192.168.62.152" />
		<constructor-arg name="port" value="7007" />
	</bean>
	<bean id="culster7008" class="redis.clients.jedis.HostAndPort">
		<constructor-arg name="host" value="192.168.62.152" />
		<constructor-arg name="port" value="7008" />
	</bean>
	<bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
		<property name="maxTotal" value="${im.hs.server.redis.maxTotal}" />
		<property name="minIdle" value="${im.hs.server.redis.minIdle}" />
		<property name="maxWaitMillis" value="${im.hs.server.redis.maxWaitTime}" />
		<property name="maxIdle" value="${im.hs.server.redis.maxIdle}" />
		<property name="testOnBorrow" value="${im.hs.server.redis.testOnBorrow}" />
		<property name="testOnReturn" value="true" />
		<property name="testWhileIdle" value="true" />
	</bean>


	<bean id="jc" class="redis.clients.jedis.JedisCluster">
		<constructor-arg name="nodes">
			<set>
				<ref bean="culster7001" />
				<ref bean="culster7002" />
				<ref bean="culster7003" />
				<ref bean="culster7004" />
				<ref bean="culster7005" />
				<ref bean="culster7006" />
				<ref bean="culster7007" />
				<ref bean="culster7008" />
			</set>
		</constructor-arg>
		<constructor-arg name="poolConfig"> <ref bean="poolConfig" /> </constructor-arg>
	</bean>
	
	<bean id="distributedLock" class="com.gaojiasoft.gaojiaRedis.DistributedLockManger" />

	<context:annotation-config />
</beans>

測试代码：

package com.gaojiasoft.gaojiaRedis;

import java.util.UUID;
import java.util.concurrent.TimeUnit;

import junit.framework.TestCase;

import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class ClusterJedisTester extends TestCase
{
    private Logger logger = LoggerFactory.getLogger(ClusterJedisTester.class);

    private static String[] list = new String[] { "classpath:conf/redis/spring-redis.xml" };
    
    private static ConfigurableApplicationContext context = new ClassPathXmlApplicationContext(list, true, null);
    
    DistributedLockManger  distributedLock = (DistributedLockManger)context.getBean("distributedLock");
    
    @Test
    public void testLock() throws InterruptedException
    {
        distributedLock.test();
        while(true)
        {
            Thread.sleep(1000);
        }
    }
}