设计模式学习：在支付系统中的实战应用

薛小春 发表于 2025-6-1 21:27:27

一、策略模式：灵活切换支付方式

场景需求

系统需要支持支付宝、微信支付、银联等多种支付渠道，且可能随时新增支付方式。
模式实现

[*]定义支付策略接口
public interface IPaymentStrategy
{
void ProcessPayment(decimal amount, string currency);
}
[*]实现具体支付策略类
// 支付宝策略
public class AlipayStrategy : IPaymentStrategy
{
public void ProcessPayment(decimal amount, string currency)
{
   Console.WriteLine($"支付宝支付：{amount}{currency}");
   // 调用支付宝SDK实现
}
}

// 微信支付策略（实现类似）
public class WechatPayStrategy : IPaymentStrategy { /*...*/ }
[*]创建支付上下文类
public class PaymentContext
{
private IPaymentStrategy _strategy;

public void SetStrategy(IPaymentStrategy strategy) => _strategy = strategy;

public void ExecutePayment(decimal amount, string currency)
{
   _strategy.ProcessPayment(amount, currency);
}
}二、装饰器模式：动态扩展支付功能

场景需求

为支付流程添加日志记录、风控验证等附加功能。
模式实现

public abstract class PaymentDecorator : IPaymentStrategy
{
protected IPaymentStrategy _strategy;

public PaymentDecorator(IPaymentStrategy strategy)
{
   _strategy = strategy;
}

public virtual void ProcessPayment(decimal amount, string currency)
{
   _strategy.ProcessPayment(amount, currency);
}
}

// 日志装饰器
public class LoggingDecorator : PaymentDecorator
{
public LoggingDecorator(IPaymentStrategy strategy) : base(strategy) {}

public override void ProcessPayment(decimal amount, string currency)
{
   Console.WriteLine($" 支付请求：{amount}{currency}");
   base.ProcessPayment(amount, currency);
}
}

public class RiskCheckDecorator : PaymentDecorator
{
public RiskCheckDecorator(IPaymentStrategy strategy) : base(strategy) {}
public override void ProcessPayment(decimal amount, string currency)
{
   Console.WriteLine(" 风控验证中...");
   base.ProcessPayment(amount, currency);
}
}

// 使用示例
var payment = new LoggingDecorator(new RiskCheckDecorator(new AlipayStrategy()));
payment.ProcessPayment(100, "CNY");三、工厂模式：统一支付对象创建

场景需求

根据配置参数动态创建支付策略实例。
模式实现

public class PaymentFactory
{
public static IPaymentStrategy Create(string paymentType)
{
   switch (paymentType.ToLower())
   {
         case "alipay":
            return new AlipayStrategy();
         case "wechat":
            return new WechatPayStrategy();
         case "unionpay":
            return new UnionPayStrategy();
         default:
            throw new ArgumentException("不支持的支付方式");
   }
}
}

// 调用示例
var strategy = PaymentFactory.Create("alipay");
strategy.ProcessPayment(200, "USD");四、责任链模式：支付流程处理

场景需求

处理支付请求时需要依次执行：参数校验 → 风控检查 → 实际支付 → 结果通知。
模式实现

public abstract class PaymentHandler
{
protected PaymentHandler _nextHandler;

public PaymentHandler SetNext(PaymentHandler handler)
{
   _nextHandler = handler;
   return _nextHandler;
}

public abstract void Handle(PaymentRequest request);
}

// 参数校验处理器
public class ValidationHandler : PaymentHandler
{
public override void Handle(PaymentRequest request)
{
   if (string.IsNullOrEmpty(request.OrderId))
         throw new ArgumentException("订单号无效");

   _nextHandler?.Handle(request);
}
}

// 构建处理链
var chain = new ValidationHandler();
chain.SetNext(new RiskCheckHandler())
.SetNext(new PaymentProcessorHandler())
.SetNext(new NotificationHandler());
chain.Handle(request);五、综合应用示例

[*]定义支付策略接口
public interface IPaymentStrategy
{
void ProcessPayment(decimal amount, string currency);
}
[*]实现具体支付策略类
// 支付宝策略
public class AlipayStrategy : IPaymentStrategy
{
public void ProcessPayment(decimal amount, string currency)
{
   Console.WriteLine($"支付宝支付：{amount}{currency}");
   // 调用支付宝SDK实现
}
}

// 微信支付策略（实现类似）
public class WechatPayStrategy : IPaymentStrategy { /*...*/ }// 银联支付策略（实现类似）public class UnionPayStrategy : IPaymentStrategy { /*...*/ }
[*]创建支付请求类
public class PaymentFactory
{
public static IPaymentStrategy Create(string paymentType)
{
   switch (paymentType.ToLower())
   {
         case "alipay":
            return new AlipayStrategy();
         case "wechat":
            return new WechatPayStrategy();
         case "unionpay":
            return new UnionPayStrategy();
         default:
            throw new ArgumentException("不支持的支付方式");
   }
}
}
[*]创建支付装饰类
public abstract class PaymentDecorator : IPaymentStrategy
{
protected IPaymentStrategy _strategy;

public PaymentDecorator(IPaymentStrategy strategy)
{
   _strategy = strategy;
}

public virtual void ProcessPayment(decimal amount, string currency)
{
   _strategy.ProcessPayment(amount, currency);
}
}

// 日志装饰器
public class LoggingDecorator : PaymentDecorator
{
public LoggingDecorator(IPaymentStrategy strategy) : base(strategy) {}

public override void ProcessPayment(decimal amount, string currency)
{
   Console.WriteLine($" 支付请求：{amount}{currency}");
   base.ProcessPayment(amount, currency);
}
}
[*]创建支付上下文类
public class PaymentContext
{
private IPaymentStrategy _strategy;

public void SetStrategy(IPaymentStrategy strategy) => _strategy = strategy;

public void ExecutePayment(decimal amount, string currency)
{
   new LoggingDecorator(_strategy).ProcessPayment(amount, currency);
}
}
[*]创建支付处理链类
public abstract class PaymentHandler
{
protected PaymentHandler _nextHandler;

public PaymentHandler SetNext(PaymentHandler handler)
{
   _nextHandler = handler;
   return _nextHandler;
}

public abstract void Handle(PaymentRequest request);
}

// 参数校验处理器
public class ValidationHandler : PaymentHandler
{
public override void Handle(PaymentRequest request)
{
   if (string.IsNullOrEmpty(request.OrderId))
         throw new ArgumentException("订单号无效");

   _nextHandler?.Handle(request);
}
}

// 风控检查处理器
public class RiskCheckHandler : PaymentHandler
{
public override void Handle(PaymentRequest request)
{
   Console.WriteLine(" 风控验证中...");
   _nextHandler?.Handle(request);
}
}

// 支付结果通知处理器
public class NotificationHandler : PaymentHandler
{
public override void Handle(PaymentRequest request)
{
   Console.WriteLine($"支付结果通知：{request.OrderId}");
   _nextHandler?.Handle(request);
}
}

// 实际支付处理器
public class PaymentProcessorHandler : PaymentHandler
{
public override void Handle(PaymentRequest request)
{
   Console.WriteLine($" 实际支付：{request.Amount}{request.Currency}");
   var strategy = PaymentFactory.Create(request.PaymentType);
   PaymentContext context = new PaymentContext();
   context.SetStrategy(strategy);
   context.ExecutePayment(request.Amount, request.Currency);
   _nextHandler?.Handle(request);
}
}

// 构建处理链
var chain = new ValidationHandler();
chain.SetNext(new RiskCheckHandler())
.SetNext(new PaymentProcessorHandler())
.SetNext(new NotificationHandler());
chain.Handle(request);相关代码：https://github.com/huangmingji/design-pattern-learning/tree/main/design-pattern-learning-1

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连热发表于 2025-10-21 21:45:15

感谢分享

郜庄静 发表于 2025-12-7 00:09:29

感谢分享

赙浦发表于 2025-12-30 00:43:37

谢谢楼主提供！

育局糊 发表于 2026-1-15 01:26:45

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热心回复！

院儿饯 发表于 2026-1-28 05:13:58

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荆邦发表于 2026-2-8 12:18:45

新版吗？好像是停更了吧。

亢安芙 发表于 2026-2-9 07:17:05

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叭遭段 发表于 2026-2-11 02:46:59

过来提前占个楼

孙淼淼 发表于 2026-2-12 15:53:36

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姜删懔 发表于 2026-2-13 13:32:04

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锄淫鲷 发表于 2026-2-13 22:01:19

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焦尔蕾 发表于 2026-2-21 18:15:08

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收藏一下不知道什么时候能用到

寨重发表于 2026-3-9 17:30:42

感谢发布原创作品，程序园因你更精彩

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设计模式学习：在支付系统中的实战应用