using System;
using System.Threading;

namespace ConsoleApp1
{
    class Program
    {
        //图书馆拥有的公用计算机  
        private const int ComputerNum = 3;
        private static Computer[] LibraryComputers;
        //同步信号量  
        public static Semaphore sp = new Semaphore(ComputerNum, ComputerNum);

        static void Main(string[] args)
        {
            //图书馆拥有ComputerNum台电脑  
            LibraryComputers = new Computer[ComputerNum];
            for (int i = 0; i < ComputerNum; i++)
                LibraryComputers[i] = new Computer("Computer" + (i + 1).ToString());
            int peopleNum = 0;
            Random ran = new Random();
            Thread user;
            System.Console.WriteLine("敲任意键模拟一批批的人排队使用{0}台计算机，ESC键结束模拟……", ComputerNum);
            //每次创建若干个线程，模拟人排队使用计算机  
            while (System.Console.ReadKey().Key != ConsoleKey.Escape)
            {
                peopleNum = ran.Next(0, 10);
                System.Console.WriteLine("\n有{0}人在等待使用计算机。", peopleNum);

                for (int i = 1; i <= peopleNum; i++)
                {
                    user = new Thread(UseComputer);
                    user.Start("User" + i.ToString());
                }
            }
        }

        //线程函数  
        static void UseComputer(Object UserName)
        {
            sp.WaitOne();//等待计算机可用  

            //查找可用的计算机  
            Computer cp = null;
            for (int i = 0; i < ComputerNum; i++)
                if (LibraryComputers[i].IsOccupied == false)
                {
                    cp = LibraryComputers[i];
                    break;
                }
            //使用计算机工作  
            cp.Use(UserName.ToString());

            //不再使用计算机，让出来给其他人使用  
            sp.Release();
        }
    }

    class Computer
    {
        public readonly string ComputerName = "";
        public Computer(string Name)
        {
            ComputerName = Name;
        }
        //是否被占用  
        public bool IsOccupied = false;
        //人在使用计算机  
        public void Use(String userName)
        {
            System.Console.WriteLine("{0}开始使用计算机{1}", userName, ComputerName);
            IsOccupied = true;
            Thread.Sleep(new Random().Next(1, 2000)); //随机休眠，以模拟人使用计算机  
            System.Console.WriteLine("{0}结束使用计算机{1}", userName, ComputerName);
            IsOccupied = false;
        }
    }
}

using System;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        //默认的容纳大小为“硬件线程“数
        static CountdownEvent cde = new CountdownEvent(Environment.ProcessorCount);

        static void LoadUser(object obj)
        {
            try
            {
                Console.WriteLine("ThreadId={0};当前任务:{1}正在加载User部分数据！", Thread.CurrentThread.ManagedThreadId, obj);
            }
            finally
            {
                cde.Signal();
            }
        }

        static void LoadProduct(object obj)
        {
            try
            {
                Console.WriteLine("ThreadId={0};当前任务:{1}正在加载Product部分数据！", Thread.CurrentThread.ManagedThreadId, obj);
            }
            finally
            {
                cde.Signal();
            }
        }

        static void LoadOrder(object obj)
        {
            try
            {
                Console.WriteLine("ThreadId={0};当前任务:{1}正在加载Order部分数据！", Thread.CurrentThread.ManagedThreadId, obj);
            }
            finally
            {
                cde.Signal();
            }
        }

        static void Main(string[] args)
        {
            //加载User表需要5个任务
            var userTaskCount = 5;
            //重置信号
            cde.Reset(userTaskCount);
            for (int i = 0; i < userTaskCount; i++)
            {
                Task.Factory.StartNew((obj) =>
                {
                    LoadUser(obj);
                }, i);
            }
            //等待所有任务执行完毕
            cde.Wait();
            Console.WriteLine("\nUser表数据全部加载完毕！\n");

            //加载product需要8个任务
            var productTaskCount = 8;
            //重置信号
            cde.Reset(productTaskCount);
            for (int i = 0; i < productTaskCount; i++)
            {
                Task.Factory.StartNew((obj) =>
                {
                    LoadProduct(obj);
                }, i);
            }
            cde.Wait();
            Console.WriteLine("\nProduct表数据全部加载完毕！\n");

            //加载order需要12个任务
            var orderTaskCount = 12;
            //重置信号
            cde.Reset(orderTaskCount);
            for (int i = 0; i < orderTaskCount; i++)
            {
                Task.Factory.StartNew((obj) =>
                {
                    LoadOrder(obj);
                }, i);
            }
            cde.Wait();
            Console.WriteLine("\nOrder表数据全部加载完毕！\n");

            Console.WriteLine("\n(*^__^*) 嘻嘻，恭喜你，数据全部加载完毕\n");
            Console.Read();
        }
    }
}