C# 唯一性ID生成器

 唯一性ID生成器：

using System;
using System.Collections.Generic;
using System.Text;

namespace Test.Core
{
    /// <summary>
    /// 唯一性ID生成器
    /// </summary>
    public class SFID
    {

        /// <summary>
        /// 初始基准時間戳，小於當前時間點即可
        /// 分布式項目請保持此時間戳一致
        /// </summary>
        private static long _twepoch = 0L;

        /// <summary>
        /// 毫秒計數器
        /// </summary>
        private static long sequence = 0L;

        /// <summary>
        /// 最大機器ID所占的位數
        /// </summary>
        private static long maxWorkerId = 90;

        /// <summary>
        /// 一微秒內可以產生計數，如果達到該值則等到下一微妙在進行生成
        /// </summary>
        private static long sequenceMask = 99;

        /// <summary>
        /// 最后一次的時間戳
        /// </summary>
        private static long lastTimestamp = -1L;

        /// <summary>
        /// 線程鎖對象
        /// </summary>
        private static object locker = new object();

        /// <summary>
        /// 機器碼
        /// </summary>
        private static long _workerId = 99;

        /// <summary>
        /// 機器編號
        /// </summary>
        public static long WorkerID
        {
            get { return _workerId; }
            set
            {
                if (value >= 0 && value < maxWorkerId)
                    _workerId = value;
                else
                    throw new Exception($"機器碼必須在0至{ maxWorkerId}之間");
            }
        }
        /// <summary>
        /// 獲取多個集合
        /// </summary>
        /// <param name="totalCount"></param>
        /// <returns></returns>
        public static IEnumerable<long> NewID(int totalCount)
        {
            for (var i = 0; i < totalCount; i++)
            {
                yield return NewID();
            }
        }
        /// <summary>
        /// 機器編碼的基數 
        /// </summary>
        private static long _workerBasic = 10000000000000L;

        /// <summary>
        /// 獲取新的ID
        /// </summary>
        /// <returns></returns>
        public static long NewID()
        {
            lock (locker)
            {
                //WorkerID = workId;
                long timestamp = timeGen();
                if (lastTimestamp == timestamp)
                { //同一微妙中生成ID
                    sequence++; //用&運算計算該微秒內產生的計數是否已經到達上限
                    if (sequence > sequenceMask)
                    {
                        //一微妙內產生的ID計數已達上限，等待下一微妙
                        timestamp = tillNextMillis(lastTimestamp);
                    }
                }
                else
                { //不同微秒生成ID
                    sequence = 0; //計數清0
                }
                if (timestamp < lastTimestamp)
                {
                    //如果當前時間戳比上一次生成ID時時間戳還小，拋出異常，因為不能保證現在生成的ID之前沒有生成過
                    throw new Exception($"Clock moved backwards.  Refusing to generate id for {lastTimestamp - timestamp} milliseconds");
                }
                lastTimestamp = timestamp; //把當前時間戳保存為最后生成ID的時間戳

                return WorkerID * _workerBasic + lastTimestamp * 100 + sequence;
            }
        }

        ///// <summary>
        ///// 獲取新的ID
        ///// </summary>
        ///// <param name="workId"></param>
        ///// <returns></returns>
        //public static long NewID(int workId)
        //{
        //    WorkerID = workId;
        //    return NewID();
        //}


        /// <summary>
        /// 獲取下一微秒時間戳
        /// </summary>
        /// <param name="lastTimestamp"></param>
        /// <returns></returns>
        private static long tillNextMillis(long lastTimestamp)
        {
            long timestamp = timeGen();
            while (timestamp <= lastTimestamp)
            {
                timestamp = timeGen();
            }
            sequence = 0;
            return timestamp;
        }

        private static DateTime _date = new DateTime(2019, 1, 1, 0, 0, 0, DateTimeKind.Utc);
        /// <summary>
        /// 當前時間戳
        /// </summary>
        /// <returns></returns>
        private static long timeGen()
        {
            return (long)(DateTime.UtcNow - _date).TotalMilliseconds;
        }


    }
}

調用：

long ID = SFID.NewID();