原型模式

Posted 2020-11-20 wskxy

1.回顾单例模式(Singleton Pattern)

　　设置一个静态的构造函数，让Student仅能被new一个，给所有调用返回一个相同的实例

　　StudentPrototype类代码如下：

using System;
using System.Threading;
namespace Prototype
{
    class StudentPrototype
    {
        public String Name="kxy";
        private StudentPrototype()
        {
            Thread.Sleep(2000);
            Console.WriteLine("执行StudentPrototype构造函数");
        }
        private static StudentPrototype _studentPrototype=null;
        static StudentPrototype()
        {
            _studentPrototype = new StudentPrototype();
        }
        public static StudentPrototype GetStudent()
        {
            return _studentPrototype;
        }
    }
}

　　Program代码如下：

using System;

namespace Prototype
{
    class Program
    {
        static void Main(string[] args)
        {
            StudentPrototype studentPrototype1 = StudentPrototype.GetStudent();
            studentPrototype1.Name = "flt";
            StudentPrototype studentPrototype2 = StudentPrototype.GetStudent();
            studentPrototype2.Name = "wzz";
            StudentPrototype studentPrototype3 = StudentPrototype.GetStudent();
            StudentPrototype studentPrototype4 = StudentPrototype.GetStudent();
            Console.Read();
        }
    }
}

　　因为studentPrototype1和studentPrototype2是调用了同个实例，所以

　　当执行studentPrototype2.Name = "wzz"时，studentPrototype1的Name属性也会变成wzz

　　同理，studentPrototype3、studentPrototype4也是使用这个实例

2.原型模式（Prototype Pattern）