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;
    }
}

生成方法：

/// <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);
        }
    }

字符串处理：

/// <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;
        }
    }