C# .NET短唯一标识符
我需要.NET中的唯一标识符(无法使用GUID,因为它对于这种情况来说太长)C# .NET短唯一标识符,c#,.net,uniqueidentifier,C#,.net,Uniqueidentifier,我需要.NET中的唯一标识符(无法使用GUID,因为它对于这种情况来说太长) code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber); 人们认为所使用的算法是一个很好的候选算法吗?或者你还有其他建议吗?这一个很好- code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId,
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
人们认为所使用的算法是一个很好的候选算法吗?或者你还有其他建议吗?这一个很好-
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
还有这里
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
您可以使用Base64:
string base64Guid = Convert.ToBase64String(Guid.NewGuid().ToByteArray());
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
这将生成一个类似于e1hkfn68pkms5zsvkonw==的字符串。因为GUID是
始终为128位,您可以省略您知道将始终为的==
在结尾出现,这将给你一个22个字符的字符串。这
但它没有YouTube那么短
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
标识值在数据库中应该是唯一的,但您应该知道其局限性。。。例如,它使批量数据插入基本上不可能,如果您处理大量记录,这将使您的速度减慢
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
您还可以使用日期/时间值。我见过几个数据库,它们使用日期/时间作为主键,虽然它不是超级干净的,但可以工作。如果控制插入,可以有效地保证代码中的值是唯一的。对于我的本地应用程序,我使用基于时间的方法:
/// <summary>
/// Returns all ticks, milliseconds or seconds since 1970.
///
/// 1 tick = 100 nanoseconds
///
/// Samples:
///
/// Return unit value decimal length value hex length
/// --------------------------------------------------------------------------
/// ticks 14094017407993061 17 3212786FA068F0 14
/// milliseconds 1409397614940 13 148271D0BC5 11
/// seconds 1409397492 10 5401D2AE 8
///
/// </summary>
public static string TickIdGet(bool getSecondsNotTicks, bool getMillisecondsNotTicks, bool getHexValue)
{
string id = string.Empty;
DateTime historicalDate = new DateTime(1970, 1, 1, 0, 0, 0);
if (getSecondsNotTicks || getMillisecondsNotTicks)
{
TimeSpan spanTillNow = DateTime.UtcNow.Subtract(historicalDate);
if (getSecondsNotTicks)
id = String.Format("{0:0}", spanTillNow.TotalSeconds);
else
id = String.Format("{0:0}", spanTillNow.TotalMilliseconds);
}
else
{
long ticksTillNow = DateTime.UtcNow.Ticks - historicalDate.Ticks;
id = ticksTillNow.ToString();
}
if (getHexValue)
id = long.Parse(id).ToString("X");
return id;
}
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
//
///返回自1970年以来的所有滴答声、毫秒或秒。
///
///1滴答=100纳秒
///
///样本:
///
///返回单位值十进制长度值十六进制长度
/// --------------------------------------------------------------------------
///刻度14094017407993061 17 3212786FA068F0 14
///毫秒1409397614940 13 148271D0BC5 11
///秒1409397492 10 5401D2AE 8
///
///
公共静态字符串TickIdGet(bool getSecondsNotTicks、bool getmillisondsnotticks、bool getHexValue)
{
string id=string.Empty;
DateTime historicalDate=新的日期时间(1970,1,1,0,0);
if(GetSecondSnoticks | | GetMillistSecondSnoticks)
{
TimeSpan spanTillNow=DateTime.UtcNow.Subtract(历史日期);
如果(获取第二个snotticks)
id=String.Format(“{0:0}”,spanTillNow.TotalSeconds);
其他的
id=String.Format(“{0:0}”,spanTillNow.total毫秒);
}
其他的
{
long ticksTillNow=DateTime.UtcNow.Ticks-historicalDate.Ticks;
id=ticksTillNow.ToString();
}
if(getHexValue)
id=long.Parse(id).ToString(“X”);
返回id;
}
据我所知,-事实上,它远非独一无二
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
我所知道的保证全球唯一性的最短的事情是。在这篇链接文章中,他讨论了缩短GUID的多种方法,最后通过via将其缩减为20个字节
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
但是,如果您确实需要一个长度不超过15字节的解决方案,恐怕您别无选择,只能使用不保证全局唯一的解决方案。在这里,我的解决方案对于并发不安全,每秒不超过1000个GUID,并且线程安全
public static class Extensors
{
private static object _lockGuidObject;
public static string GetGuid()
{
if (_lockGuidObject == null)
_lockGuidObject = new object();
lock (_lockGuidObject)
{
Thread.Sleep(1);
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
var epochLong = Convert.ToInt64((DateTime.UtcNow - epoch).TotalMilliseconds);
return epochLong.DecimalToArbitrarySystem(36);
}
}
/// <summary>
/// Converts the given decimal number to the numeral system with the
/// specified radix (in the range [2, 36]).
/// </summary>
/// <param name="decimalNumber">The number to convert.</param>
/// <param name="radix">The radix of the destination numeral system (in the range [2, 36]).</param>
/// <returns></returns>
public static string DecimalToArbitrarySystem(this long decimalNumber, int radix)
{
const int BitsInLong = 64;
const string Digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
if (radix < 2 || radix > Digits.Length)
throw new ArgumentException("The radix must be >= 2 and <= " + Digits.Length.ToString());
if (decimalNumber == 0)
return "0";
int index = BitsInLong - 1;
long currentNumber = Math.Abs(decimalNumber);
char[] charArray = new char[BitsInLong];
while (currentNumber != 0)
{
int remainder = (int)(currentNumber % radix);
charArray[index--] = Digits[remainder];
currentNumber = currentNumber / radix;
}
string result = new String(charArray, index + 1, BitsInLong - index - 1);
if (decimalNumber < 0)
{
result = "-" + result;
}
return result;
}
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
公共静态类扩展名
{
私有静态对象_lockGuidObject;
公共静态字符串GetGuid()
{
if(_lockGuidObject==null)
_lockGuidObject=新对象();
锁(_lockGuidObject)
{
睡眠(1);
var epoch=新的日期时间(1970,1,1,0,0,0,DateTimeKind.Utc);
var epochLong=Convert.ToInt64((DateTime.UtcNow-epoch).total毫秒);
返回epochLong.DecimalToArbitrarySystem(36);
}
}
///
///将给定的十进制数转换为具有
///指定的基数(范围为[2,36])。
///
///要转换的数字。
///目标数字系统的基数(在[2,36]范围内)。
///
公共静态字符串DecimalTorBitrarySystem(此长小数,整数基数)
{
常数int位长=64;
常量字符串数字=“0123456789abcdefghijklmnopqrstuvxyz”;
if(基数<2 | |基数>位数.长度)
抛出新ArgumentException(“基数必须>=2且如果你的应用程序没有几百万人,在同一毫秒内使用生成短的唯一字符串,你可以考虑使用下面的函数
private static readonly Object obj = new Object();
private static readonly Random random = new Random();
private string CreateShortUniqueString()
{
string strDate = DateTime.Now.ToString("yyyyMMddhhmmssfff");
string randomString ;
lock (obj)
{
randomString = RandomString(3);
}
return strDate + randomString; // 16 charater
}
private string RandomString(int length)
{
const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxy";
var random = new Random();
return new string(Enumerable.Repeat(chars, length)
.Select(s => s[random.Next(s.Length)]).ToArray());
}
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
如果您只需要在下一个99年使用您的应用程序,请将yyyy更改为yy。
更新20160511:更正随机函数
-添加锁对象
将随机变量移出RandomString函数
我知道离发布日期很远……:)
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
我有一个只生成9个六进制字符的生成器,例如:C9D6F7FF3、C9D6FB52C
public class SlimHexIdGenerator : IIdGenerator
{
private readonly DateTime _baseDate = new DateTime(2016, 1, 1);
private readonly IDictionary<long, IList<long>> _cache = new Dictionary<long, IList<long>>();
public string NewId()
{
var now = DateTime.Now.ToString("HHmmssfff");
var daysDiff = (DateTime.Today - _baseDate).Days;
var current = long.Parse(string.Format("{0}{1}", daysDiff, now));
return IdGeneratorHelper.NewId(_cache, current);
}
}
static class IdGeneratorHelper
{
public static string NewId(IDictionary<long, IList<long>> cache, long current)
{
if (cache.Any() && cache.Keys.Max() < current)
{
cache.Clear();
}
if (!cache.Any())
{
cache.Add(current, new List<long>());
}
string secondPart;
if (cache[current].Any())
{
var maxValue = cache[current].Max();
cache[current].Add(maxValue + 1);
secondPart = maxValue.ToString(CultureInfo.InvariantCulture);
}
else
{
cache[current].Add(0);
secondPart = string.Empty;
}
var nextValueFormatted = string.Format("{0}{1}", current, secondPart);
return UInt64.Parse(nextValueFormatted).ToString("X");
}
}
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
公共类SlimHexIdGenerator:IIdGenerator
{
私有只读日期时间_baseDate=新日期时间(2016,1,1);
私有只读IDictionary_cache=new Dictionary();
公共字符串NewId()
{
var now=DateTime.now.ToString(“HHmmssfff”);
var daysDiff=(DateTime.Today-_baseDate).Days;
var current=long.Parse(string.Format(“{0}{1}”),daysDiff,now));
返回IdGeneratorHelper.NewId(_缓存,当前);
}
}
静态类IdGeneratorHelper
{
公共静态字符串NewId(IDictionary缓存,长当前)
{
if(cache.Any()&&cache.Keys.Max()
您可以使用
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
它的6
字符很好,599527
,143354
code = await UserManager.GenerateChangePhoneNumberTokenAsync(input.UserId, input.MobileNumber);
当我们
public static string ToTinyUuid(this Guid guid)
{
return Convert.ToBase64String(guid.ToByteArray())[0..^2] // remove trailing == padding
.Replace('+', '-') // escape (for filepath)
.Replace('/', '_'); // escape (for filepath)
}
Guid.NewGuid().ToTinyUuid()
private static readonly object _getUniqueIdLock = new object();
public static string GetUniqueId()
{
lock(_getUniqueIdLock)
{
System.Threading.Thread.Sleep(1);
return DateTime.UtcNow.Ticks.ToString("X");
}
}
// Our url safe, base 64 alphabet:
const string alphabet = "-_0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
// Sanitized Guid string. Preserve the last two hex chars
var guidStr = "929F7C4D4B2644E1A122A379C02D6345";
var lastTwo = guidStr.Substring(30, 2);
string shortGuid = "";
// Iterate over the ten groups of 3 hex chars: 929 F7C 4D4 B26 44E 1A1 22A 379 C02 D63
for (var i = 0; i < 10; i++)
{
var hex = guidStr.Substring(i*3, 3); // Get the next 3 hex chars
var x = Convert.ToInt32(hex, 16); // Convert to int
shortGuid += $"{alphabet[x/64]}{alphabet[x%64]}"; // Lookup the two-digit base64 value
}
shortGuid += lastTwo; // Don't forget the last two
Console.WriteLine(shortGuid);
yDXWhiGAfc4v6EbTK0Px45
Guid.NewGuid().ToString("n")
5db4cee3bfd8436395d37fca2d48d5b3
82fac271c76148a3a0667c00a5da990d