C#如何实现Snowflake算法

Snowflake 是 Twitter 开源的分布式 ID 生成算法，它可以在不依赖数据库的情况下生成全局唯一的 ID。下面是一个简单的 C# 实现：

using System;  public class Snowflake {     // 基准时间     private static readonly DateTime Epoch = new DateTime(2021, 1, 1, 0, 0, 0, DateTimeKind.Utc);      // 机器 ID 所占位数     private const int WorkerIdBits = 5;      // 数据中心 ID 所占位数     private const int DatacenterIdBits = 5;      // 序列号所占位数     private const int SequenceBits = 12;      // 机器 ID 左移位数     private const int WorkerIdShift = SequenceBits;      // 数据中心 ID 左移位数     private const int DatacenterIdShift = SequenceBits + WorkerIdBits;      // 时间戳左移位数     private const int TimestampLeftShift = SequenceBits + WorkerIdBits + DatacenterIdBits;      // 最大序列号     private const long MaxSequence = (1L << SequenceBits) - 1;      // 机器 ID 和数据中心 ID 的最大值     private const long MaxWorkerId = (1L<< WorkerIdBits) - 1;     private const long MaxDatacenterId = (1L<< DatacenterIdBits) - 1;      // 机器 ID     private readonly long _workerId;      // 数据中心 ID     private readonly long _datacenterId;      // 序列号     private long _sequence;      // 上次生成 ID 的时间戳     private long _lastTimestamp;      public Snowflake(long workerId, long datacenterId, long sequence = 0L)     {         if (workerId < 0 || workerId > MaxWorkerId)             throw new ArgumentException($"Worker Id must be between 0 and {MaxWorkerId}");          if (datacenterId < 0 || datacenterId > MaxDatacenterId)             throw new ArgumentException($"Datacenter Id must be between 0 and {MaxDatacenterId}");          _workerId = workerId;         _datacenterId = datacenterId;         _sequence = sequence;     }      public long NextId()     {         lock (this)         {             var timestamp = GetCurrentTimestamp();              if (timestamp < _lastTimestamp)                 throw new Exception("Invalid system clock");              if (_lastTimestamp == timestamp)             {                 _sequence = (_sequence + 1) & MaxSequence;                 if (_sequence == 0)                     timestamp = WaitNextMillisecond(_lastTimestamp);             }             else             {                 _sequence = 0;             }              _lastTimestamp = timestamp;             return ((timestamp - Epoch.Ticks)<< TimestampLeftShift) |                    (_datacenterId<< DatacenterIdShift) |                    (_workerId<< WorkerIdShift) |                    _sequence;         }     }      private long GetCurrentTimestamp()     {         return (DateTime.UtcNow - Epoch).Ticks / 10000;     }      private long WaitNextMillisecond(long lastTimestamp)     {         var timestamp = GetCurrentTimestamp();         while (timestamp <= lastTimestamp)             timestamp = GetCurrentTimestamp();         return timestamp;     } } 

使用方法：

var snowflake = new Snowflake(1, 1); var id = snowflake.NextId(); Console.WriteLine(id); 

这个实现中，我们使用了一个基准时间（Epoch），机器 ID（workerId），数据中心 ID（datacenterId）和序列号（sequence）来生成全局唯一的 ID。你需要为每个工作节点分配一个唯一的机器 ID 和数据中心 ID。