java 用redis如何处理电商平台，秒杀、抢购超卖

这是在一个方法调用下面代码的部分

if (!this.checkSoldCountByRedisDate(key, limitCount, buyCount, endDate)) {// 标注10：
				throw new ServiceException("您购买的商品【" + commodityTitle + "】,数量已达到活动限购量");
			}

2、下面是判断超卖的方法

	//标注：1；synchronized 
	private synchronized boolean checkSoldCountByRedisDate(String key, int limitCount, int buyCount, Date endDate) {
		boolean flag = false;
		if (redisUtil.exists(key)) {//标注:2;redisUtil.exists(key)
			Integer soldCount = (int) redisUtil.get(key);//标注：3；redisUtil.get(key)
			Integer totalSoldCount = soldCount + buyCount;
			if (limitCount > (totalSoldCount)) {
				flag = false;//标注：4；flag = false
			} else {
				if (redisUtil.tryLock(key, 80)) {//标注：5；rdisUtil.tryLock(key, 80)
 
					redisUtil.remove(key);// 解锁 //标注：6；redisUtil.remove(key)
 
					redisUtil.set(key, totalSoldCount);//标注：7；redisUtil.set(key, totalSoldCount)
 
					flag = true;
				} else {
					throw new ServiceException("活动太火爆啦,请稍后重试");
				}
			}
		} else {
			//标注:8;redisUtil.set(key, new String("buyCount"), DateUtil.diffDateTime(endDate, new Date()))
			redisUtil.set(key, new String("buyCount"), DateUtil.diffDateTime(endDate, new Date()));
			flag = false;
		}
		return flag;
	}

3、上面提到的redisUtil类中的方法，其中redisTemplate为org.springframework.data.redis.core.RedisTemplate;这个不了解的可以去网上找下，spring-data-redis.jar的相关文档，贴出来redisUtil用到的相关方法：

	public boolean exists(final String key) {
		return redisTemplate.hasKey(key);
	}
	
	public boolean tryLock(String key, long timeout) {
		boolean isSuccess = redisTemplate.opsForValue().setIfAbsent(key, "");
		if (isSuccess) {//标注：9；redisTemplate.expire
 
			redisTemplate.expire(key, timeout, TimeUnit.MILLISECONDS);
		}
		return isSuccess;
	}
	
	public Object get(final String key) {
		Object result = null;
		ValueOperations operations = redisTemplate.opsForValue();
		result = operations.get(key);
		return result;
	}
	
	public void remove(final String key) {
		if (exists(key)) {
			redisTemplate.delete(key);
		}
	}
	
	public boolean set(final String key, Object value) {
		return set(key, value, null);
	}
	
	public boolean set(final String key, Object value, Long expireTime) {
		boolean result = false;
		try {
			ValueOperations operations = redisTemplate.opsForValue();
			operations.set(key, value);
			if (expireTime != null) {
				redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
			}
			result = true;
		} catch (Exception e) {
			e.printStackTrace();
		}
		return result;
	}