C#死锁案例代码

C#死锁案例代码

简介：

如下代码实现创建两个线程t1和t2，分别起初分配占用lock1和ock2资源。当一个线程t1占用资源lock1时，再去请求另外一个资源lock2时，此时由于另外一个线程t2在正占用资源t2，请求失败，等待释放资源。同时t2又发出请求资源lock1，但是lock1又被t1占用，没有释放，也只能进行等待。此时两个线程只能等待一直等待对方释放资源，这就称之为死锁。

namespace Deadlock
{
    class DL
    {
        int field1 = 0;
        int field2 = 0;
        private object lock1 = new int[1];
        private object lock2 = new int[1];

        public void First(int val)
        {
            lock (lock1)
            {
                Console.WriteLine("First: Acquired lock 1: "
                    + Thread.CurrentThread.GetHashCode() + " Now Sleeping.");
                
                //Try commenting Thread.Sleep()
                Thread.Sleep(1000);//此时t2线程占用资源

                Console.WriteLine("First: Acquired lock 1: "
                    + Thread.CurrentThread.GetHashCode() + " Now wants lock2.");

                //当请求锁lock2时，lock被t2线程占用，等待释放
                lock (lock2)
                {
                    Console.WriteLine("First: Acquired lock 2: "
                        + Thread.CurrentThread.GetHashCode());
                    field1 = val;
                    field2 = val;
                }
            }
        }

        public void Second(int val)
        {
            lock (lock2)
            {
                Console.WriteLine("Second: Acquired lock 2: "
                    + Thread.CurrentThread.GetHashCode());
                //当请求锁lock1时，lock1被t1线程占用，等待释放
                lock (lock1)
                {
                    Console.WriteLine("Second: Acquired lock 1: "
                        + Thread.CurrentThread.GetHashCode());
                    field1 = val;
                    field2 = val;
                }
            }
        }
    }

    public class MainApp
    {
        DL d = new DL();

        public static void Main()
        {
            MainApp m = new MainApp();
            Thread t1 = new Thread(new ThreadStart(m.Run1));
            t1.Start();
            Thread t2 = new Thread(new ThreadStart(m.Run2));
            t2.Start();
            Console.ReadLine();
        }

        public void Run1()
        {
            this.d.First(10);
        }

        public void Run2()
        {
            this.d.Second(10);
        }
    }
}