java 实现 类似 reids nx锁 , 模拟秒杀操作
依赖:
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>23.0</version>
</dependency>
package com.sea.shop.common.util; import com.google.common.cache.Cache; import com.google.common.cache.CacheBuilder; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; /*************************** *<pre> * @Project Name : shop_research * @Package : com.sea.shop.common.util * @File Name : MyNxLockUtils * @Author : Sea * @Date : 7/26/22 11:46 AM * @Purpose : * @History : *</pre> ***************************/ public class MyNxLockUtils { private static volatite String lcPoint0="xx0"; private static valatite String lcPoint1="xx1"; private static valatite String lcPoint2="xx2"; private static volatile String lcPoint3="xx3"; private static volatite String lcPoint4="xx4"; private static volatite String lcPoint5="xx5"; private static volatite String lcPoint6="xx6"; private static volatite String lcPoint7="xx7"; private static volatite String lcPoint8="xx8"; private static volatite String lcPoint9="xx9"; /** * 分段枷锁,提升效率 * @param k * @return */ private static String getLcPoint(String k){ switch (k.hashCode()%10){ case 1: return lcPoint1; case 2: return lcPoint2; case 3: return lcPoint3; case 4: return lcPoint4; case 5: return lcPoint5; case 6: return lcPoint6; case 7: return lcPoint7; case 8: return lcPoint8; case 9: return lcPoint9; default: return lcPoint0; } } private static Cache<String, String> lockCache = null; static { lockCache = CacheBuilder.newBuilder().expireAfterWrite(12, TimeUnit.SECONDS).build(); } /** * @param k * @param v * @return */ public static Boolean getLock(String k, String v){ if(lockCache.getIfPresent(k)==null) { synchronized (getLcPoint(k)){ if(lockCache.getIfPresent(k)==null){ lockCache.put(k,v); return true; } } } return false; } public static void unlock(String k, String v) { String ifPresent = lockCache.getIfPresent(k); if(ifPresent!=null&&ifPresent.equals(v)){ lockCache.invalidate(k); } } /** * @param k * @param v * @param acquireTimeOutSec * @return */ public static Boolean getLock(String k, String v,Long acquireTimeOutSec){ long expTime = System.currentTimeMillis()+ TimeUnit.SECONDS.toMillis(acquireTimeOutSec); while (true) { try { Boolean lock = getLock(k, v); if(lock) { return true; } Thread.sleep(15l); if(System.currentTimeMillis()-expTime>0){ return false; } }catch (Exception e) { return false; } } } //模拟库存 private static volatile int no =1000; public static void main(String[] args) { ExecutorService cachePool = Executors.newFixedThreadPool(32); long start = System.currentTimeMillis(); int threadNo = 100; for(int i=1;i<=threadNo;i++) { cachePool.submit(()-> { Boolean lock = false; while (true) { lock = getLock("1", "1"); if(lock) { try { int myNo = no--; //扣减库存 Thread.sleep(100); System.err.println(myNo); unlock("1","1"); break; } catch (InterruptedException e) { e.printStackTrace(); unlock("1","1"); } } } }); } ThreadPoolExecutor cachePool1 = (ThreadPoolExecutor) cachePool; while (true){ long completedTaskCount = cachePool1.getCompletedTaskCount(); if(completedTaskCount==threadNo){ System.err.println("last no is :"+ no); System.err.println("total cost time :"+(System.currentTimeMillis()-start)); break; } } } }