C#【多线程-线程同步】-SemaphoreSlim业务应用场景

SemaphoreSlim业务应用场景

一.首先说一下SemaphoreSlim

   1.什么是SemaphoreSlim？

   官网上面解释： 对可同时访问资源或资源池的线程数加以限制的  Semaphore 的轻量替代。

  个人理解：对同一个资源，多个线程同时并发访问，起到对线程数控制的作用。

 

二.业务场景进行理解

  比如，售票窗口，需要开两个窗口售票，买票人员只能在这两个窗口买票

 

 三.建一个控制台

 

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace _05SemaphoreSlim
{
    class Program
    {
//定义两个信号量（两个窗口）
       private static SemaphoreSlim semaphore = new SemaphoreSlim (2);
       // A padding interval to make the output more orderly.
       private static int padding;

       static void AccessDatabase(string name ,int seconds)
       {
          semaphore.Wait();
          Console.WriteLine("wait to access base{0}",
                                name);
          
          Console.WriteLine("wait ganted to access base{0}",
                               name);
          Thread.Sleep(seconds);
          Console.WriteLine("completed ganted to access base{0}",
                               name);
          semaphore.Release();
       }
       public static void Main()
       {
          for (int i=1;i<70;i++)
          {
              string name = "Thread"+i;
              int s = 2 + 2 * i;
              var t = new Thread(()=> AccessDatabase(name, s));
             t.Start();

          }

       }
    }
}

 

Wait: 假如当前信号量不到2个，wait方法将不进行阻塞暂停，如果信号量未2个，当前线程执行到wait方法进行暂停，等待其它线程释放 信号量+1

Release：释放线程，信号量-1