【设计模式】工厂方法（FactoryMethod）模式

看不见PPT的请自行解决DNS污染问题。

相关类的代码：

 namespace FactoryPatternConsole.Model
 {
     public class Address
     {
         public string CountryCode { get; set; }
     }
 }

Address

 namespace FactoryPatternConsole.Model
 {
     public class Order
     {
         public decimal TotalCost { get; set; }
         public decimal WeightInKG { get; set; }
         public string CourierTrackingId { get; set; }
         public Address DispatchAddress { get; set; }
     }
 }

Order

 namespace FactoryPatternConsole.Model
 {
     public interface IShippingCourier
     {
         string GenerateConsignmentLabelFor(Address address);
     }
 }

IShippingCourier

 namespace FactoryPatternConsole.Model
 {
     public class DHL : IShippingCourier
     {
         public string GenerateConsignmentLabelFor(Address address)
         {
             return "DHL-XXXX-XXXX-XXXX";
         }
     }
 }

DHL

 namespace FactoryPatternConsole.Model
 {
     public class RoyalMail:IShippingCourier
     {
         public string GenerateConsignmentLabelFor(Address address)
         {
             return "RM-XXXX-XXXX-XXXX";
         }
     }
 }

RoyalMail

 using FactoryPatternConsole.Model;

 namespace FactoryPatternConsole.Factory
 {
     public static class UKShippingCourierFactory
     {
         public static IShippingCourier CreateShippingCourier(Order order)
         {
             if (order.TotalCost >  || order.WeightInKG > )
             {
                 return new DHL();
             }
             else
             {
                 return new RoyalMail();
             }
         }
     }
 }

UKShippingCourierFactory

 using FactoryPatternConsole.Factory;
 using FactoryPatternConsole.Model;

 namespace FactoryPatternConsole.Service
 {
     public class OrderService
     {
         public void Dispatch(Order order)
         {
             IShippingCourier shippingCourier = UKShippingCourierFactory.CreateShippingCourier(order);

             order.CourierTrackingId = shippingCourier.GenerateConsignmentLabelFor(order.DispatchAddress);
         }
     }
 }

OrderService

---

测试用代码：

 using FactoryPatternConsole.Model;
 using FactoryPatternConsole.Service;
 using System;

 namespace FactoryPatternConsole
 {
     class Program
     {
         static void Main(string[] args)
         {
             OrderService service = new OrderService();
             foreach (Order order in GetOrders())
             {
                 service.Dispatch(order);
                 Console.WriteLine(string.Format("TotalCost:{0}, WeightInKG:{1}, CourierTrackingId:{2}",
                     order.TotalCost, order.WeightInKG, order.CourierTrackingId));
             }
             Console.ReadLine();
         }

         public static Order[] GetOrders()
         {
             return new Order[] {
                 new Order()
                 {
                     TotalCost = ,
                     WeightInKG = ,
                     DispatchAddress = new Address() { CountryCode = "CN" },
                 },
                 new Order()
                 {
                     TotalCost = 100.1m,
                     WeightInKG = ,
                     DispatchAddress = new Address() { CountryCode = "CN" },
                 },
                 new Order()
                 {
                     TotalCost = ,
                     WeightInKG = 5.1m,
                     DispatchAddress = new Address() { CountryCode = "CN" },
                 },
             };
         }
     }
 }

Program

---

执行结果：