工厂方法 学习手记

概述

      简单工厂存在着不少的缺点，工厂类就违反了“对扩展开放、对修改关闭”的原则。而工厂方法可以克服简单工厂的缺点。

工厂方法通过定义一个用户创建对象的接口，让子类决定实例化哪一个类。Factory Method使一个类的实例化延迟到其子类。 

 

 实现例子：

 产品接口：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleFactoryMethodDemo
{
    internal interface FemaleClothes
    {
         String Name { get; set; }

         String Code { get; set; }

         void Display();
        
    }

 }

具体产品类A：

 using System;

using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleFactoryMethodDemo
{
    internal class FemaleShirtClothes : FemaleClothes
    {
        private String name="衬衫";

        public String Name
        {
            get { return name="衬衫"; }
            set { name="衬衫"; }
        }

        private String code="ChenShan";

        public String Code
        {
            get { return code="ChenShan"; }
            set { code="ChenShan"; }
        }
        

        public void Display()
        {
            Console.WriteLine("商品名称是:"+Name+" 拼音是:"+Code);
        }
    }
}

 具体产品类B：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleFactoryMethodDemo
{
    internal class FemaleTshirtsClothes : FemaleClothes
    {
        private String name="T恤";

        public String Name
        {
            get { return name="T恤"; }
            set { name="T恤"; }
        }

        private String  code="T-Shirts";

        public String Code     
        {
            get { return code ="T-Shirts"; }
            set { code = "T-Shirts"; }
        }

        public void Display()
        {
            Console.WriteLine("商品名称是:" + Name + " 拼音是:" + Code);
        }
        
    }

 }

抽象工厂：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleFactoryMethodDemo
{
    internal interface FemaleClothesFactory
    {
        FemaleClothes GetInstance();
    }

}

 具体工厂A：

 using System;

using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleFactoryMethodDemo
{
    internal class FemaleShirtClothesFactory : FemaleClothesFactory
    {
        FemaleShirtClothes clothes;

        public FemaleClothes GetInstance()
        {
            clothes= new FemaleShirtClothes();
            return clothes;
        }
    }
}

具体工厂B：

 using System;

using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleFactoryMethodDemo
{
    internal class FemaleTshirtsClothesFactory:FemaleClothesFactory
    {
        FemaleTshirtsClothes clothes;

        public FemaleClothes GetInstance()
        {
            clothes = new FemaleTshirtsClothes();
            return clothes;
        }
    }
}

 客户端调用：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleFactoryMethodDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            FemaleClothesFactory factory = new FemaleShirtClothesFactory();

            FemaleClothes clothes = factory.GetInstance();

            clothes.Display();

            Console.ReadLine();

        }
    }

 }

 工厂方法，克服了简单工厂的“开放-封闭”原则，同时将具体对象的创建工作延迟到子类，更具体扩展能力，较好的解决了这种紧耦合的关系。