static void Main(string[] args)
{
CSRedisClient redisClient = new CSRedis.CSRedisClient("127.0.0.1:6379,defaultDatabase=0");
var lockKey = "lockKey";
var stockKey = "stock";
redisClient.Set(stockKey, 5); //商品库存
var releaseLockScript = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end"; //释放锁的redis脚本
redisClient.Del(lockKey); //测试前,先把锁删了.
Parallel.For(0, 10, i =>
{
var id = Guid.NewGuid().ToString("N");
//获取锁
do
{
//set : key存在则失败,不存在才会成功,并且过期时间5秒
var success = redisClient.Set(lockKey, id, expireSeconds: 5, exists: RedisExistence.Nx);
if (success == true)
{
break;
}
Thread.Sleep(TimeSpan.FromSeconds(1));//休息1秒再尝试获取锁
} while (true);
Console.WriteLine($"线程:{Task.CurrentId} 拿到了锁,开始消费");
//扣减库存
var currentStock = redisClient.IncrBy(stockKey, -1);
if (currentStock < 0)
{
Console.WriteLine($"库存不足,线程:{Task.CurrentId} 抢购失败!");
redisClient.Eval(releaseLockScript, lockKey, id);
return;
}
//模拟处理业务,这里不考虑失败的情况
Thread.Sleep(TimeSpan.FromSeconds(new Random().Next(1, 3)));
Console.WriteLine($"线程:{Task.CurrentId} 消费完毕!剩余 {currentStock} 个");
//业务处理完后,释放锁.
redisClient.Eval(releaseLockScript, lockKey, id);
});
}
/// <summary>
/// 清空购物车
/// </summary>
/// <param name="openId"></param>
/// <returns></returns>
public void ClearCar(string openId)
{
_client.Del(openId);
GetCarList(openId);
}
