redis分布式秒杀锁-CSDN博客
tjk 2023-10-08 18:37:46 2023-10-08 0 0
-- 获取锁标识,是否与当前线程一致?if(redis.call('get', KEYS[1]) == ARGV[1]) then -- 一致,删除 return redis.call('del', KEYS[1])end-- 不一致,直接返回return 0
package com.platform.lock;public interface ILock { /** * 获取锁 * @param timeoutSec * @return */ public boolean tryLock(long timeoutSec); /** * 锁标识、释放锁 */ public void unlock();}
package com.platform.lock;import cn.hutool.core.lang.UUID;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.core.io.ClassPathResource;import org.springframework.data.redis.core.StringRedisTemplate;import org.springframework.data.redis.core.script.DefaultRedisScript;import org.springframework.stereotype.Service;import java.util.Collections;import java.util.concurrent.TimeUnit;/** * redis的分布式锁 * 实现ILock接口 */public class SimpleRedisLock implements ILock { // 不同的业务有不同的锁名称 private String name; private StringRedisTemplate stringRedisTemplate; private static final String KEY_PREFIX = "tryLock:"; private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-"; // DefaultRedisScript, private static final DefaultRedisScript<Long> UNLOCK_SCRIPT; public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) { this.name = name; this.stringRedisTemplate = stringRedisTemplate; } // 初始化 UNLOCK_SCRIPT,用静态代码块的方式,一加载SimpleRedisLock有会加载unlock.lua // 避免每次调unLock() 才去加载,提升性能!!! static { UNLOCK_SCRIPT = new DefaultRedisScript<>(); // setLocation() 设置脚本位置 UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua")); // 返回值类型 UNLOCK_SCRIPT.setResultType(Long.class); } /** * 获取锁 */ @Override public boolean tryLock(long timeoutSec) { // 获取线程标示 String threadId = ID_PREFIX + Thread.currentThread().getId(); // 获取锁 // set lock thread1 nx ex 10 // nx : setIfAbsent(如果不存在) , ex : timeoutSec(秒) Boolean success = stringRedisTemplate.opsForValue() .setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS); // 自动拆箱(Boolean -> boolean)!!!可能有风险 return Boolean.TRUE.equals(success); } /** * 解决判断(锁标识、释放锁)这两个动作,之间产生阻塞!!! * JVM的 FULL GC * 要让这两个动作具有原子性 */ @Override public void unlock() { // 调用lua脚本 stringRedisTemplate.execute( UNLOCK_SCRIPT, Collections.singletonList(KEY_PREFIX + name), ID_PREFIX + Thread.currentThread().getId()); }}
@PostMapping("/cancelPublicBenefit") @CheckRepeatCommit public RestResponse cancelPublicBenefit(@LoginUser MallUserEntity loginUser, @RequestBody MallPublicBenefitEntity publicBenefitEntity) { String key = PUBLIC_BENEFIT_TEAM_LOCK_FLAG + publicBenefitEntity.getId(); RestResponse restResponse = null; SimpleRedisLock simpleRedisLock = new SimpleRedisLock(key,stringRedisTemplate); try { if (simpleRedisLock.tryLock(15)) { // 成功获取锁,执行业务逻辑 restResponse = mallPublicBenefitService.cancelPublicBenefit(loginUser, publicBenefitEntity); } else { // 获取锁失败,处理失败逻辑 throw new BusinessException("服务器繁忙!"); } } finally { simpleRedisLock.unlock(); } return restResponse; }