網(wǎng)上大部分C#寫的都有點(diǎn)亂糟糟，我簡化了一下。這個(gè)算法總體思想是生成一個(gè)64位整數(shù)，前42位放從前某特定時(shí)間點(diǎn)到當(dāng)前時(shí)間的毫秒數(shù)，中間10位放生成id的機(jī)器的唯一編碼，后12位放順序號(hào)（如果同一毫秒內(nèi)生成多次，此順序號(hào)可避免產(chǎn)生重復(fù)id）

using System;

namespace xxx
{
    /// <summary>
    /// Id 生成類
    /// </summary>
    class Snowflake
    {
        private const string LOCK_OBJ = "76003AEB-E3F9-460A-BD31-D9AE9E7684C0";

        private const int MACHINE_BIT_SIZE = 10; // 機(jī)器編號(hào)長度10位
        private const int SEQUENCE_BIT_SIZE = 12; // 序號(hào)長度12位

        private static Snowflake _snowflake;

        private long _machineNumber; // 機(jī)器序號(hào)
        private long _timestamp; // 時(shí)間戳
        private long _sequence; // 序號(hào)

        private Snowflake() { }

        /// <summary>
        /// 設(shè)置機(jī)器序號(hào)
        /// </summary>
        public int MachineNumber
        {
            set { _machineNumber = value; }
        }

        /// <summary>
        /// 得到一個(gè)實(shí)例
        /// </summary>
        /// <returns></returns>
        public static Snowflake GetInstance()
        {
            if (_snowflake == null)
            {
                lock (LOCK_OBJ)
                {
                    if (_snowflake == null)
                    {
                        _snowflake = new Snowflake();
                    }
                }
            }
            return _snowflake;
        }

        /// <summary>
        /// 產(chǎn)生一個(gè)id，由時(shí)間戳、機(jī)器編碼、順序號(hào)組成
        /// </summary>
        /// <returns></returns>
        public long GenerateId(Func<DateTime> GetTime)
        {
            lock (LOCK_OBJ)
            {
                if (_machineNumber > (-1L ^ -1L << MACHINE_BIT_SIZE))
                {
                    throw new ArgumentException("機(jī)器編號(hào)超出最大值");
                }

                long timestamp = GetTimestamp(GetTime());
                if (timestamp < _timestamp)
                {
                    throw new ArgumentException("時(shí)間戳錯(cuò)誤");
                }

                if (timestamp == _timestamp)
                {
                    _sequence++;
                    if (_sequence > (-1L ^ -1L << SEQUENCE_BIT_SIZE))
                    {
                        while (true) // 序號(hào)已用完，等下一毫秒
                        {
                            timestamp = GetTimestamp(GetTime());
                            if (timestamp > _timestamp)
                            {
                                _sequence = 0;
                                break;
                            }
                        }
                    }
                }
                else
                {
                    _sequence = 0;
                }

                long id = timestamp << (MACHINE_BIT_SIZE + SEQUENCE_BIT_SIZE) 
                    | _machineNumber << SEQUENCE_BIT_SIZE 
                    | _sequence;

                _timestamp = timestamp;

                return id;
            }
        }

        // 當(dāng)前時(shí)間戳
        private long GetTimestamp(DateTime now)
        {
            return (long)(now - new DateTime(2024, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;
        }
    }
}

調(diào)用：

using System;

namespace xxx
{
    public class IdGenerator
    {
        /// <summary>
        /// 生成Id
        /// </summary>
        /// <returns></returns>
        public static long GenerateId()
        {
            Snowflake sf = Snowflake.GetInstance();
            sf.MachineNumber = YourGetMachineNumberFunction();
            long id = sf.GenerateId(GetTime);
            return id;
        }

        private static DateTime GetTime()
        {
            return YourGetNowTimeFunction();
        }
    }
}