基於redis叢集實現的分散式鎖，可用於秒殺商品的庫存數量管理，有測試程式碼(何志雄)
阿新 • • 發佈：2018-12-25
轉載請標明出處。
在分散式系統中，經常會出現需要競爭同一資源的情況，本程式碼基於redis3.0.1+jedis2.7.1實現了分散式鎖。
可用於例如秒殺系統中的商品庫存的管理。付完整程式碼及測試用例。
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; /** * 分散式鎖管理器，支援對單個資源加鎖解鎖，或給一批資源的批量加鎖及解鎖 * @ClassName: DistributedLockManger * @Description: * @author 何志雄 001 * @company 南京高嘉軟體技術有限公司 * @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的變數無法註解 @Autowired JedisCluster jc; private static DistributedLockManger lockManger; public DistributedLockManger() { } @PostConstruct public void init() { lockManger = this; lockManger.jc = this.jc; } /** * 獲取鎖 如果鎖可用 立即返回true， 否則立即返回false，作為非阻塞式鎖使用 * @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; } /** * 鎖在給定的等待時間內空閒，則獲取鎖成功 返回true， 否則返回false，作為阻塞式鎖使用 * @param key 鎖鍵 * @param value 被誰鎖定 * @param timeout 嘗試獲取鎖時長，建議傳遞500,結合實踐單位，則可表示500毫秒 * @param unit，建議傳遞TimeUnit.MILLISECONDS * @return * @throws InterruptedException */ public static boolean tryLock(String key , String value , long timeout , TimeUnit unit) throws InterruptedException { //納秒 long begin = System.nanoTime(); do { //LOGGER.debug("{}嘗試獲得{}的鎖.", value, key); Long i = lockManger.jc.setnx(key, value); if (i == 1) { lockManger.jc.expire(key, DEFAULT_SINGLE_EXPIRE_TIME); LOGGER.debug("{}成功獲取{}的鎖,設定鎖過期時間為{}秒 ", value, key, DEFAULT_SINGLE_EXPIRE_TIME); return true; } else { // 存在鎖 ，但可能獲取不到，原因是獲取的一剎那間 // String desc = lockManger.jc.get(key); // LOGGER.error("{}正被{}鎖定.", key, desc); } if (timeout == 0) { break; } //在其睡眠的期間，鎖可能被解，也可能又被他人佔用，但會嘗試繼續獲取鎖直到指定的時間 Thread.sleep(100); } while ((System.nanoTime() - begin) < unit.toNanos(timeout)); //因超時沒有獲得鎖 return false; } /** * 釋放單個鎖 * @param key 鎖鍵 * @param value 被誰釋放 */ public static void unLock(String key , String value) { try { lockManger.jc.del(key); LOGGER.debug("{}鎖被{}釋放 .", 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++) { //隨機產生一個使用者 userId = UUID.randomUUID().toString(); //該使用者試圖鎖定(如果被鎖，嘗試等待300毫秒)，在處理一些事情後，再釋放鎖 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 { //獲取鎖，如果不能立即獲取，嘗試等待1000毫秒 boolean isLock = DistributedLockManger.tryLock(key, value, 500, TimeUnit.MILLISECONDS); if (isLock) { //doSomething(佔用鎖20毫秒到4秒，模擬處理事務) long doSomeThingTime = RandomUtils.nextLong(20, 4000); LOGGER.debug("{}將持有鎖{}時長{}毫秒.", value, key, doSomeThingTime); Thread.sleep(doSomeThingTime); //然後釋放鎖 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
#最大閒置連線數
im.hs.server.redis.maxIdle=500
#最大連線數，超過此連線時操作redis會報錯
im.hs.server.redis.maxTotal=5000
im.hs.server.redis.maxWaitTime=1000
im.hs.server.redis.testOnBorrow=true
#最小閒置連線數，spring啟動的時候自動建立該數目的連線供應用程式使用，不夠的時候會申請。
im.hs.server.redis.minIdle=300spring-redis.xml
測試程式碼：<?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" /> <!-- 事實上，只需要連線1個節點就可以 --> <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>
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); } } }