如何在Java中实现行为的动态替换_利用多态提升可扩展性

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

public class WeChatPay implements PaymentMethod {
    public void pay(double amount) {
        System.out.println("使用微信支付 " + amount + " 元");
    }
}

public class AliPay implements PaymentMethod {
    public void pay(double amount) {
        System.out.println("使用支付宝支付 " + amount + " 元");
    }
}

public class PaymentProcessor {
    private PaymentMethod method;

    public PaymentProcessor(PaymentMethod method) {
        this.method = method;
    }

    public void execute(double amount) {
        method.pay(amount);
    }
}

PaymentProcessor processor = new PaymentProcessor(new AliPay());
processor.execute(100); // 输出：使用支付宝支付 100.0 元

processor = new PaymentProcessor(new WeChatPay());
processor.execute(150); // 输出：使用微信支付 150.0 元

public class PaymentFactory {
    public static PaymentMethod getMethod(String type) {
        return switch (type) {
            case "wechat" -> new WeChatPay();
            case "alipay" -> new AliPay();
            default -> throw new IllegalArgumentException("不支持的支付方式: " + type);
        };
    }
}

PaymentMethod method = PaymentFactory.getMethod("wechat");
new PaymentProcessor(method).execute(200);