base62与long的相互转换

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public static class Converter {     private static String keys = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";//编码,可加一些字符也可以实现72,96等任意进制转换，但是有符号数据不直观，会影响阅读。     private static int exponent = keys.Length;//幂数       /// <summary>     /// decimal value type to 62 string     /// </summary>     /// <param name="value">The max value can not more decimal.MaxValue<</param>     /// <returns>Return a specified 62 encode string</returns>     public static string ToBase62(this long value)//17223472558080896352ul     {         string result = string.Empty;         do         {             var index = value % exponent;             result = keys[(int)index] + result;             value = (value - index) / exponent;         }         while (value > 0);           return result;     }         /// <summary>     /// 62 encode string to decimal     /// </summary>     /// <param name="value">62 encode string</param>     /// <returns>Return a specified decimal number that decode by 62 string</returns>     public static long FromBase62(this string value)//bUI6zOLZTrj     {         long result = 0;         for (int i = 0; i < value.Length; i++)         {             int x = value.Length - i - 1;             result += keys.IndexOf(value[i]) * Pow(exponent, x);// Math.Pow(exponent, x);         }         return result;     }       /// <summary>     /// 一个数据的N次方     /// </summary>     /// <param name="x"></param>     /// <returns></returns>     private static long Pow(long baseNo, long x)     {         long value = 1;////1 will be the result for any number's power 0.任何数的0次方，结果都等于1         while (x > 0)         {             value = value * baseNo;             x--;         }         return value;     } }

　　

 

 

https://www.cnblogs.com/Jeremys/p/3796466.html