/// <summary>
/// 根据GUID获取唯一数字序列
/// </summary>
public static long GuidToInt64()
{byte[] bytes = Guid.NewGuid().ToByteArray();return BitConverter.ToInt64(bytes, 0);
}

/// <summary>
/// Generate a new <see cref="Guid"/> using the comb algorithm.
/// </summary>
private Guid GenerateComb()
{byte[] guidArray = Guid.NewGuid().ToByteArray();DateTime baseDate = new DateTime(1900, 1, 1);DateTime now = DateTime.Now;// Get the days and milliseconds which will be used to build    //the byte string    TimeSpan days = new TimeSpan(now.Ticks - baseDate.Ticks);TimeSpan msecs = now.TimeOfDay;// Convert to a byte array        // Note that SQL Server is accurate to 1/300th of a    // millisecond so we divide by 3.333333    byte[] daysArray = BitConverter.GetBytes(days.Days);byte[] msecsArray = BitConverter.GetBytes((long)(msecs.TotalMilliseconds / 3.333333));// Reverse the bytes to match SQL Servers ordering    Array.Reverse(daysArray);Array.Reverse(msecsArray);// Copy the bytes into the guid    Array.Copy(daysArray, daysArray.Length - 2, guidArray,guidArray.Length - 6, 2);Array.Copy(msecsArray, msecsArray.Length - 4, guidArray,guidArray.Length - 4, 4);return new Guid(guidArray);
}

/// <summary>/// From: https://github.com/twitter/snowflake/// An object that generates IDs./// This is broken into a separate class in case/// we ever want to support multiple worker threads/// per process/// </summary>public class IdWorker{private long workerId;private long datacenterId;private long sequence = 0L;private static long twepoch = 1288834974657L;private static long workerIdBits = 5L;private static long datacenterIdBits = 5L;private static long maxWorkerId = -1L ^ (-1L << (int)workerIdBits);private static long maxDatacenterId = -1L ^ (-1L << (int)datacenterIdBits);private static long sequenceBits = 12L;private long workerIdShift = sequenceBits;private long datacenterIdShift = sequenceBits + workerIdBits;private long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;private long sequenceMask = -1L ^ (-1L << (int)sequenceBits);private long lastTimestamp = -1L;private static object syncRoot = new object();public IdWorker(long workerId, long datacenterId){// sanity check for workerIdif (workerId > maxWorkerId || workerId < 0){throw new ArgumentException(string.Format("worker Id can't be greater than %d or less than 0", maxWorkerId));}if (datacenterId > maxDatacenterId || datacenterId < 0){throw new ArgumentException(string.Format("datacenter Id can't be greater than %d or less than 0", maxDatacenterId));}this.workerId = workerId;this.datacenterId = datacenterId;}public long nextId(){lock (syncRoot){long timestamp = timeGen();if (timestamp < lastTimestamp){throw new ApplicationException(string.Format("Clock moved backwards.  Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));}if (lastTimestamp == timestamp){sequence = (sequence + 1) & sequenceMask;if (sequence == 0){timestamp = tilNextMillis(lastTimestamp);}}else{sequence = 0L;}lastTimestamp = timestamp;return ((timestamp - twepoch) << (int)timestampLeftShift) | (datacenterId << (int)datacenterIdShift) | (workerId << (int)workerIdShift) | sequence;}}protected long tilNextMillis(long lastTimestamp){long timestamp = timeGen();while (timestamp <= lastTimestamp){timestamp = timeGen();}return timestamp;}protected long timeGen(){return (long)(DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;}}

private static void TestIdWorker(){HashSet<long> set = new HashSet<long>();IdWorker idWorker1 = new IdWorker(0, 0);IdWorker idWorker2 = new IdWorker(1, 0);Thread t1 = new Thread(() => DoTestIdWoker(idWorker1, set));Thread t2 = new Thread(() => DoTestIdWoker(idWorker2, set));t1.IsBackground = true;t2.IsBackground = true;t1.Start();t2.Start();try{Thread.Sleep(30000);t1.Abort();t2.Abort();}catch (Exception e){}Console.WriteLine("done");}private static void DoTestIdWoker(IdWorker idWorker, HashSet<long> set){while (true){long id = idWorker.nextId();if (!set.Add(id)){Console.WriteLine("duplicate:" + id);}Thread.Sleep(1);}}