/// 
    /// 动态生产有规律的ID Snowflake算法是Twitter的工程师为实现递增而不重复的ID实现的    /// http://blog.csdn.net/w200221626/article/details/52064976         /// C# 实现 Snowflake算法     /// 
    public class Snowflake    {        private static long machineId;//机器ID        private static long datacenterId = 0L;//数据ID        private static long sequence = 0L;//计数从零开始        private static long twepoch = 687888001020L; //唯一时间随机量        private static long machineIdBits = 5L; //机器码字节数        private static long datacenterIdBits = 5L;//数据字节数        public static long maxMachineId = -1L ^ -1L << (int)machineIdBits; //最大机器ID        private static long maxDatacenterId = -1L ^ (-1L << (int)datacenterIdBits);//最大数据ID        private static long sequenceBits = 12L; //计数器字节数，12个字节用来保存计数码                private static long machineIdShift = sequenceBits; //机器码数据左移位数，就是后面计数器占用的位数        private static long datacenterIdShift = sequenceBits + machineIdBits;        private static long timestampLeftShift = sequenceBits + machineIdBits + datacenterIdBits; //时间戳左移动位数就是机器码+计数器总字节数+数据字节数        public static long sequenceMask = -1L ^ -1L << (int)sequenceBits; //一微秒内可以产生计数，如果达到该值则等到下一微妙在进行生成        private static long lastTimestamp = -1L;//最后时间戳        private static object syncRoot = new object();//加锁对象        static Snowflake snowflake;        public static Snowflake Instance()        {            if (snowflake == null)                snowflake = new Snowflake();            return snowflake;        }        public Snowflake()        {            Snowflakes(0L, -1);        }        public Snowflake(long machineId)        {            Snowflakes(machineId, -1);        }        public Snowflake(long machineId, long datacenterId)        {            Snowflakes(machineId, datacenterId);        }        private void Snowflakes(long machineId, long datacenterId)        {            if (machineId >= 0)            {                if (machineId > maxMachineId)                {                    throw new Exception("机器码ID非法");                }                Snowflake.machineId = machineId;            }            if (datacenterId >= 0)            {                if (datacenterId > maxDatacenterId)                {                    throw new Exception("数据中心ID非法");                }                Snowflake.datacenterId = datacenterId;            }        }        /// 
        /// 生成当前时间戳        /// 
        /// 
     
      毫秒
             private static long GetTimestamp()        {            //让他2000年开始            return (long)(DateTime.UtcNow - new DateTime(2000, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;        }        /// 
        /// 获取下一微秒时间戳        /// 
        ///         /// 
             private static long GetNextTimestamp(long lastTimestamp)        {            long timestamp = GetTimestamp();            int count = 0;            while (timestamp <= lastTimestamp)//这里获取新的时间,可能会有错,这算法与comb一样对机器时间的要求很严格            {                count++;                if (count > 10)                    throw new Exception("机器的时间可能不对");                Thread.Sleep(1);                timestamp = GetTimestamp();            }            return timestamp;        }        /// 
        /// 获取长整形的ID        /// 
        /// 
             public long GetId()        {            lock (syncRoot)            {                long timestamp = GetTimestamp();                if (Snowflake.lastTimestamp == timestamp)                { //同一微妙中生成ID                    sequence = (sequence + 1) & sequenceMask; //用&运算计算该微秒内产生的计数是否已经到达上限                    if (sequence == 0)                    {                        //一微妙内产生的ID计数已达上限，等待下一微妙                        timestamp = GetNextTimestamp(Snowflake.lastTimestamp);                    }                }                else                {                    //不同微秒生成ID                    sequence = 0L;                }                if (timestamp < lastTimestamp)                {                    throw new Exception("时间戳比上一次生成ID时时间戳还小，故异常");                }                Snowflake.lastTimestamp = timestamp; //把当前时间戳保存为最后生成ID的时间戳                long Id = ((timestamp - twepoch) << (int)timestampLeftShift)                    | (datacenterId << (int)datacenterIdShift)                    | (machineId << (int)machineIdShift)                    | sequence;                return Id;            }        }    }

[TestClass]    public class SnowflakeUnitTest1    {        /// 
        /// 动态生产有规律的ID Snowflake算法是Twitter的工程师为实现递增而不重复的ID实现的        /// 
        [TestMethod]        public void SnowflakeTestMethod1()        {            var ids = new List
     
      ();            for (int i = 0; i < 1000000; i++)//测试同时100W有序ID            {                ids.Add(Snowflake.Instance().GetId());            }            for (int i = 0; i < ids.Count - 1; i++)            {                Assert.IsTrue(ids[i] < ids[i+1]);            }        }    }
     

namespace ConsoleApplicationTester{    class Program    {        static void Main(string[] args)        {            for (int i = 0; i < 1000; i++)            {                Console.WriteLine("开始执行 " + DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss:ffffff") + "    " + Snowflake.Instance().GetId());                Console.WriteLine("Snowflake.maxMachineId:" + Snowflake.maxMachineId);            }        }    }}