ASP.net生成各种随机数字，用于优惠券、验证码等

北京网站建设-恒动时空

将网上查到的资料收集整理如下：

1、利用GUID生成全球唯一标识符，长度为32位，格式如：6F9619FF-8B86-D011-B42D-00C04FC964FF。

SQLSERVER本身可以生成，ASP.NET也可以生成。

最简单的如：GUID guid = Guid.newguid()

2、将GUID转为哈希数，然后随机

Random rand = new Random(Guid.NewGuid().GetHashCode());

生成示例：1024588704

3、获取系统启动后经过的毫秒数，然后随机

Random rnd = new Random(Environment.TickCount);

生成示例：208439635

4、其他利用GUID生成的的方法示例：

private long GenerateId()
{
byte[] buffer = Guid.NewGuid().ToByteArray();
return BitConverter.ToInt32(buffer, 0);
}

生成：5020365391994185848

private string GenerateId(string flag)
{
long i = 1;
foreach (byte b in Guid.NewGuid().ToByteArray())
{
i *= ((int)b + 1);
}
return string.Format("{0:x}", i - DateTime.Now.Ticks);
}

生成：aded0a2611f8aa4a

5、两个用于生成不重复数字的类

public class RandomNum
{
private static char[] constant ={
'0','1','2','3','4','5','6','7','8','9', 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'
};
public static string GenerateRandom(int Length)
{
System.Text.StringBuilder newRandom = new System.Text.StringBuilder(62);
Random rd = new Random();
for (int i = 0; i < Length; i++)
{
newRandom.Append(constant[rd.Next(62)]);
}
return newRandom.ToString();
}
}

生成：EV34SOG1RGCV（可控制生成位数）

/// <summary>
/// 生成不重复乱码
/// </summary>
public class RandomNumber
{
const long MAX = 218340105584895; // ZZZZZZZZ
const long MIN = 568002355840; // 0a0000000
const int SeedQuantity = 1; // 随机质量，越大越慢，即使为1质量也不错

public static long[] getRandom(int size)
{
//先取一定倍量的随机种子，再从这些种子里面随机
long[] seed = getRandomSeeds(size * SeedQuantity);
long[] ranArr = new long[size];

Random rand = new Random();
for (int i = 0; i < size; i++)
{
int j = rand.Next(seed.Length - i);
ranArr[i] = seed[j];
seed[j] = seed[seed.Length - 1 - i];
}
return ranArr;
}

private static long[] getRandomSeeds(int size)
{
long[] ranArr = new long[size];
for (int i = 0; i < size; i++)
{
ranArr[i] = GetNext(i);
}
Array.Sort(ranArr); // 排序

List<int> seedRepeatPosition = new List<int>();
// 遍历一遍将重复的记录下来
long last = 0;
for (int i = 0; i < ranArr.Length; i++)
{
if (ranArr[i] == last)
{
ranArr[i] = 0;
seedRepeatPosition.Add(i);
}
else
last = ranArr[i];
}

Array.Sort(ranArr); // 排序
// 将重复的重新处理为不重复的
List<long> newseedList = new List<long>();
long newseed;
for (int i = 0; i < seedRepeatPosition.Count; i++)
{
do
{

newseed = GetNext(i);
} while (Array.BinarySearch(ranArr, newseed) > -1 || newseedList.Contains(newseed));

newseedList.Add(newseed);
ranArr[seedRepeatPosition[i]] = newseed;

}

return ranArr;

}
private static long GetNext(int seed)
{
int initSeed = (int)(DateTime.Now.Ticks - seed * 10000);
Random ran = new Random(initSeed);
double d;
long ret;

do
{
d = ran.NextDouble();
ret = Convert.ToInt64(d * (Math.Pow(10, 15)));
}
while (ret <= MIN || ret > MAX);

return ret;
}
}

生成示例：217654655788864

6、其它

还可以利用当前时间的Ticks属性来获取不重复的数字，

如：DateTime.Now.Ticks

生成示例：634903854555468750

或者利用MD5

7.取时间戳生成随即数生成10位流水号

/// <summary>
/// 取时间戳生成随即数生成10位流水号
/// </summary>
/// <returns></returns>
public static UInt32 UnixStamp()
{
TimeSpan ts = DateTime.Now - TimeZone.CurrentTimeZone.ToLocalTime(new DateTime(1970, 1, 1));
return Convert.ToUInt32(ts.TotalSeconds);
}

8.随机数生成方法

/// <summary>
/// 取随机数
/// </summary>
/// <param name="length"></param>
/// <returns></returns>
public static string BuildRandomStr(int length)
{
Random rand = new Random();

int num = rand.Next();

string str = num.ToString();

if (str.Length > length)
{
str = str.Substring(0, length);
}
else if (str.Length < length)
{
int n = length - str.Length;
while (n > 0)
{
str.Insert(0, "0");
n--;
}
}

return str;
}

9.C# 生成一个时间戳

/// 获取时间戳
/// </summary>
/// <returns></returns>
public static string GetTimeStamp()
{
TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
return Convert.ToInt64(ts.TotalSeconds).ToString();
}