【C#教程】深入探究Guid

手写方法生成Guid

在C#的System类中已经为我们预定义了结构体Guid用于生成Guid，我们还可以通过手写方法来实现生成Guid

public static string NewGuid()
  {
      string[] a = { "A", "B", "C", "D", "E", "F", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
      StringBuilder stringBuilder = new StringBuilder();
      var r = new Random();
      Parallel.For(0, 32, 
          i => 
          {
              stringBuilder.Append(a[r.Next(0, 15)]);
          });
      return stringBuilder.ToString();
  }

效率比较

系统方法和手写代码各执行10000次，比较效率。

【C#教程】停表-StopWatch

介绍命名空间: System.Diagnostics Assemblies: System.Runtime.Extensions.dll, System.dll, netstandard.dll 提供一组方法和属性，可用于准确地测量运行时间。 public class Stopwatch 继承 O...

using System;
  using System.Collections.Generic;
  using System.Diagnostics;
  using System.Linq;
  using System.Text;
  using System.Threading.Tasks;
  
  namespace GUID
  {
      class Program
      {
          public static string NewGuid()
          {
              string[] a = { "A", "B", "C", "D", "E", "F", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0" };
              StringBuilder stringBuilder = new StringBuilder(100);
              var r = new Random();
              Parallel.For(0, 32, 
                  i => 
                  {
                      stringBuilder.Append(a[r.Next(0, 15)]);
                  });
              return stringBuilder.ToString();
          }
          static void Main(string[] args)
          {
              Stopwatch sw = new Stopwatch();
              sw.Start();
              for (int i = 1; i <= 10000; i++)
              {
                  var guid = Guid.NewGuid();
                  guid.ToString("N");
              }
              sw.Stop();
              Console.WriteLine("系统方法总共花费{0}ms.", sw.ElapsedMilliseconds);
  
              sw.Reset();
              sw.Start();
              for (int i = 1; i <= 10000; i++)
              {
                  NewGuid();
              }
              sw.Stop();
              Console.WriteLine("手写方法总共花费{0}ms.", sw.ElapsedMilliseconds);
  
              Console.ReadKey();
          }
      }
  }

最终结果

手写方法完败 😈

系统方法总共花费4ms.
  手写方法总共花费106ms.

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