C# 生成不重复的短字符串

/// <summary>
/// 可用字符
/// </summary>
static char[] sc;
/// <summary>
/// 起始时间
/// </summary>
static DateTime startTime;

/// <summary>
/// 字符串前缀
/// </summary>
static long prve = 0;
/// <summary>
/// 位数设置
/// </summary>
static int len = 0;

/// <summary>
/// 锁
/// </summary>
static readonly object _lock = new object();

/// <summary> /// 创建一个在本地唯一的短字符串生成对象 /// </summary> public MyConsoleDemoModule() {     if (sc == null)     {         //根据需求可加入小写abcdefghijklmnopqrstuvwxyz         sc = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();         //起始时间越大，时间戳就越小，字符串才能越短         startTime = new DateTime(2024, 10, 12, 0, 0, 0, 0);         //位数设置         len = 8;     } }

    /// <summary>     /// 生成一个唯一的短字符串     /// </summary>     public string Create()     {         lock (_lock)         {             //使用时间戳确保不会重复             TimeSpan ts = DateTime.UtcNow - startTime;             //毫秒1000*10，每秒自增（0-9999）             long tempSeconds = Convert.ToInt64(ts.TotalMilliseconds * 10);             //防重复冗余设置（前缀自增，未超过当前时间戳就用）             prve = tempSeconds > prve ? tempSeconds : prve++;             //获取字符串             return GetShortString(prve, len);         }     }

    /// <summary>     /// 使用进制生成短字符串     /// </summary>     /// <param name="num">毫秒自增时间戳</param>     /// <param name="len">位数设置</param>     /// <returns></returns>     private string GetShortString(long num, int len)     {         var str = "";         while (num >= sc.Length)         {             //取余赋值             str = sc[num % sc.Length] + str;             num = num / sc.Length;         }         var ret = sc[num] + str;          if (ret.Length > len)         {             return ret.Substring(0, len);         }         else         {             var pre = string.Empty;             for (int x = 0; x < len - ret.Length; x++)             {                 Random random = new Random();                 //随机取字符串数组字符                 var index = random.Next(0, (sc.Length - 1));                 //累加字符串                 pre += sc[index];             }             //拼接             return pre + ret;         }     }