@Autowired
    RedisTemplate redisTemplate;
 
    /**
     * redis分布式鎖演示案例，此處使用redisTemplate
     * @param stockId  此處以扣減庫(kù)存為例子，stockId代表要扣減庫(kù)存的商品id,庫(kù)存數(shù)據(jù)是提前存在redis的，并和數(shù)據(jù)庫(kù)進(jìn)行同步
     * @return
     */
    public AjaxResult redisLockDemo(String stockId){
        //鎖前綴
        final String stock_lock = "stock_lock:";
        // 生成一個(gè)隨機(jī)唯一的值用于辨別鎖的使用對(duì)象
        String clientId = UUID.randomUUID().toString();
        //此處使用set(k,v,time,unit)來獲取鎖，確保加鎖和設(shè)置超時(shí)時(shí)間是原子操作
        Boolean lock = redisTemplate.opsForValue().setIfAbsent(stock_lock + stockId, clientId, 10, TimeUnit.MILLISECONDS);
        if (!lock){
            //獲取鎖失敗
            return AjaxResult.error("服務(wù)器繁忙，請(qǐng)稍后再試！");
        }
        //獲取鎖成功
        //執(zhí)行扣減庫(kù)存
        try {
            int stock = (int) redisTemplate.opsForValue().get(stockId);
            if (stock > 0){
                int realStock = stock - 1;
                // 重新設(shè)置庫(kù)存數(shù)據(jù)
                redisTemplate.opsForValue().set(stockId, realStock + "");
                // .............其他步驟
                log.info("庫(kù)存扣減成功{}", stockId);
            } else {
                return AjaxResult.error("商品已經(jīng)被搶光了！");
            }
        } finally {
           //釋放鎖
//            if (clientId.equals(stringRedisTemplate.opsForValue().get(stock_lock + stockId))){
//                stringRedisTemplate.delete(stock_lock + stockId);
//            }
            //此處使用lua腳本釋放鎖，具有原子性
            String script = "local lockKey = KEYS[1]\n" +
                    "local clientId = ARGV[1]\n" +
                    "local currentHolder = redis.call('GET', lockKey)\n" +
                    "if currentHolder == clientId then\n" +
                    "    redis.call('DEL', lockKey)\n" +
                    "    return true\n" +
                    "else\n" +
                    "    return false\n" +
                    "end";
            DefaultRedisScript<Boolean> redisScript = new DefaultRedisScript<>(script, Boolean.class);
            Boolean result = (Boolean) redisTemplate.execute(redisScript, Collections.singletonList(stock_lock + stockId), clientId);
 
            if (result != null && result) {
               log.info("所釋放成功");
            } else {
                log.info("所釋放失敗");
            }
        }
        return AjaxResult.success("扣減庫(kù)存成功！");
    }

    @Autowired
    Redisson redisson; 
/**
     * redis分布式鎖演示案例，redisson
     * @param stockId  此處以扣減庫(kù)存為例子，stockId代表要扣減庫(kù)存的商品id,庫(kù)存數(shù)據(jù)是提前存在redis的，并和數(shù)據(jù)庫(kù)進(jìn)行同步
     * @return
     */
    public AjaxResult redissonLockDemo(String stockId){
        final String lockKey = "stock_lock:";
        RLock lock = redisson.getLock(lockKey);
        lock.lock();
        try {
            //執(zhí)行扣減庫(kù)存
            int stock = (int) redisTemplate.opsForValue().get(stockId);
            if (stock > 0){
                int realStock = stock - 1;
                // 重新設(shè)置庫(kù)存數(shù)據(jù)
                redisTemplate.opsForValue().set(stockId, realStock + "");
                // .............其他步驟
                log.info("庫(kù)存扣減成功{}", stockId);
            } else {
                return AjaxResult.error("商品已經(jīng)被搶光了！");
            }
        }finally {
            lock.unlock();
        }
        return AjaxResult.success("扣減庫(kù)存成功！");
    }