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在此之前，去看了下Redission的實(shí)現(xiàn)原理，不過(guò)在開(kāi)發(fā)中，原本的代碼使用RedistTemplate實(shí)現(xiàn)的，也不太想換，所以我想了下，不如自己實(shí)現(xiàn)要給WatchDog。
我的想法是，在用戶(hù)加上鎖的時(shí)候開(kāi)啟個(gè)定時(shí)任務(wù)線程，并且在定時(shí)任務(wù)中，判斷原線程isAlive狀態(tài)進(jìn)行“續(xù)命”。
下面是代碼(在這里面為了方便，未使用的是HuTool.CornUtil來(lái)實(shí)現(xiàn)動(dòng)態(tài)定時(shí)任務(wù))：
/** * Title * * @ClassName: LockUtil * @Description:鎖工具類(lèi),通過(guò)內(nèi)部枚舉類(lèi)實(shí)現(xiàn)單例，防止反射攻擊 * @author: Karos * @date: 2023/1/4 0:17 * @Blog: https://www.wzl1.top/ */package cn.katool.lock;import cn.hutool.core.util.BooleanUtil;import cn.hutool.core.util.ObjectUtil;import cn.hutool.cron.CronUtil;import cn.hutool.cron.task.Task;import cn.katool.Config.LockConfig;import cn.katool.Exception.ErrorCode;import cn.katool.Exception.KaToolException;import cn.katool.other.MethodIntefaceUtil;import com.qiniu.util.StringUtils;import lombok.SneakyThrows;import lombok.extern.slf4j.Slf4j;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Scope;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.stereotype.Component;import org.springframework.util.ObjectUtils;import javax.annotation.Resource;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.TimeUnit;@Component@Scope("prototype")@Slf4jpublic class LockUtil { @Resource RedisTemplate redisTemplate; private LockUtil(){ } private static boolean isOpenCorn=false; /** * 帶看門(mén)狗機(jī)制上鎖 * @param lockObj * @return */ public boolean DistributedLock(Object lockObj){ try { return DistributedLock(lockObj,null,null); } catch (KaToolException e) { throw new RuntimeException(e); } } @Resource LockConfig lockConfig; //加鎖 /** * 無(wú)看門(mén)狗機(jī)制上鎖 * @param obj * @param exptime * @param timeUnit * @return * @throws KaToolException */ public boolean DistributedLock(Object obj,Long exptime,TimeUnit timeUnit) throws KaToolException { if (ObjectUtil.isEmpty(obj)){ throw new KaToolException(ErrorCode.PARAMS_ERROR," Lock=> 傳入obj為空"); } Boolean isDelay=false; if (ObjectUtil.isAllEmpty(exptime,timeUnit)){ isDelay=true; } if(ObjectUtil.isEmpty(exptime)){ exptime= lockConfig.getInternalLockLeaseTime();; } if (ObjectUtils.isEmpty(timeUnit)){ timeUnit=lockConfig.getTimeUnit(); } //線程被鎖住了，就一直等待 DistributedAssert(obj); Boolean aBoolean = redisTemplate.opsForValue().setIfAbsent("Lock:"+obj.toString(), "1", exptime, timeUnit); log.info("katool=> LockUntil => DistributedLock:{} value:{} extime:{} timeUnit:{}",obj.toString(), "1", exptime, timeUnit); //實(shí)現(xiàn)看門(mén)狗 if (isDelay){ if (LockUtil.isOpenCorn==false){ //如果同一個(gè)項(xiàng)目之前打開(kāi)過(guò)，那么先關(guān)閉，避免重復(fù)啟動(dòng) CronUtil.stop(); //支持秒級(jí)別定時(shí)任務(wù) CronUtil.setMatchSecond(true); //定時(shí)服務(wù)啟動(dòng) CronUtil.start(); LockUtil.isOpenCorn=true; } Thread thread = Thread.currentThread(); TimeUnit finalTimeUnit = timeUnit; Long finalExptime = exptime; class TempClass{ public String scheduleId; } final TempClass tempClass = new TempClass(); tempClass.scheduleId=CronUtil.schedule("0/30 * * * * ?", new Task() { @SneakyThrows @Override public void execute() { boolean alive = thread.isAlive(); if (alive) { delayDistributedLock(obj, finalExptime>=3?(finalExptime / 3):finalExptime, finalTimeUnit); return; } else { if (tempClass.scheduleId==null||"".equals(tempClass.scheduleId)){ return; } CronUtil.remove(tempClass.scheduleId); DistributedUnLock(obj); return; } } }); } return BooleanUtil.isTrue(aBoolean); } //檢鎖 public void DistributedAssert(Object obj) throws KaToolException { if (ObjectUtils.isEmpty(obj)){ throw new KaToolException(ErrorCode.PARAMS_ERROR," Lock=> 傳入obj為空"); } while(true){ Object o = redisTemplate.opsForValue().get("Lock:" + obj.toString()); if (ObjectUtils.isEmpty(o))return; } } //延期 public boolean delayDistributedLock(Object obj,Long exptime,TimeUnit timeUnit) throws KaToolException { if (ObjectUtils.isEmpty(obj)){ throw new KaToolException(ErrorCode.PARAMS_ERROR," Lock=> 傳入obj為空"); } Boolean aBoolean = redisTemplate.opsForValue().setIfPresent("Lock:"+obj.toString(), "1", exptime, timeUnit); log.info("katool=> LockUntil => delayDistributedLock:{} value:{} extime:{} timeUnit:{}",obj.toString(), "1", exptime, timeUnit); return BooleanUtil.isTrue(aBoolean); } //釋放鎖 public boolean DistributedUnLock(Object obj) throws KaToolException { if (ObjectUtils.isEmpty(obj)){ throw new KaToolException(ErrorCode.PARAMS_ERROR," Lock=> 傳入obj為空"); } Boolean aBoolean = redisTemplate.delete("Lock:" + obj.toString()); log.info("katool=> LockUntil => unDistributedLock:{} isdelete:{} ",obj.toString(),true); return BooleanUtil.isTrue(aBoolean); } //利用枚舉類(lèi)實(shí)現(xiàn)單例模式，枚舉類(lèi)屬性為靜態(tài)的 private enum SingletonFactory{ Singleton; LockUtil lockUtil; private SingletonFactory(){ lockUtil=new LockUtil(); } public LockUtil getInstance(){ return lockUtil; } } @Bean("LockUtil") public static LockUtil getInstance(){ return SingletonFactory.Singleton.lockUtil; }}關(guān)鍵詞：
責(zé)任編輯：Rex_22
