java使用策略模式完成多种支付方式代码实现

策略模式是一种行为型设计模式，它定义了一系列的算法，并将每个算法封装到独立的类中，使得它们可以互相替换。在这个问题中，我们可以使用策略模式来实现多种支付方式。

首先，我们需要创建一个接口，定义支付方式的通用行为：

public interface PaymentStrategy {
    void pay(double amount);
}

然后，我们可以创建不同的支付方式类，实现接口中的方法：

public class CreditCardStrategy implements PaymentStrategy {
    private String cardNumber;
    private String cvv;
    private String expiryDate;

    public CreditCardStrategy(String cardNumber, String cvv, String expiryDate) {
        this.cardNumber = cardNumber;
        this.cvv = cvv;
        this.expiryDate = expiryDate;
    }

    @Override
    public void pay(double amount) {
        // 实现信用卡支付的逻辑
        System.out.println(amount + " paid with credit card");
    }
}

public class PayPalStrategy implements PaymentStrategy {
    private String email;
    private String password;

    public PayPalStrategy(String email, String password) {
        this.email = email;
        this.password = password;
    }

    @Override
    public void pay(double amount) {
        // 实现PayPal支付的逻辑
        System.out.println(amount + " paid with PayPal");
    }
}

public class AliPayStrategy implements PaymentStrategy {
    private String account;
    private String password;

    public AliPayStrategy(String account, String password) {
        this.account = account;
        this.password = password;
    }

    @Override
    public void pay(double amount) {
        // 实现支付宝支付的逻辑
        System.out.println(amount + " paid with AliPay");
    }
}

最后，我们可以创建一个使用支付策略的类：

public class PaymentContext {
    private PaymentStrategy paymentStrategy;

    public PaymentContext(PaymentStrategy paymentStrategy) {
        this.paymentStrategy = paymentStrategy;
    }

    public void pay(double amount) {
        paymentStrategy.pay(amount);
    }
}

使用示例：

public class Main {
    public static void main(String[] args) {
        PaymentContext paymentContext = new PaymentContext(new CreditCardStrategy("1234567890", "123", "01/23"));
        paymentContext.pay(100.0);

        paymentContext = new PaymentContext(new PayPalStrategy("test@example.com", "password"));
        paymentContext.pay(200.0);

        paymentContext = new PaymentContext(new AliPayStrategy("test@example.com", "password"));
        paymentContext.pay(300.0);
    }
}

输出结果：

100.0 paid with credit card
200.0 paid with PayPal
300.0 paid with AliPay

这样就完成了使用策略模式实现多种支付方式的代码实现。不同的支付方式被封装到不同的类中，通过创建不同的支付策略对象，可以在运行时选择不同的支付方式进行支付