在Java中如何使用多态优化代码扩展性_多态应用实践指南

public interface Payment {
    void pay(double amount);
}
<p>public class Alipay implements Payment {
public void pay(double amount) {
System.out.println("使用支付宝支付：" + amount);
}
}</p><p>public class WeChatPay implements Payment {
public void pay(double amount) {
System.out.println("使用微信支付：" + amount);
}
}</p>

Payment payment = new Alipay();
payment.pay(100); // 输出：使用支付宝支付：100
<p>payment = new WeChatPay();
payment.pay(200); // 输出：使用微信支付：200</p>

public class PaymentFactory {
    public static Payment getPayment(String type) {
        switch (type) {
            case "alipay": return new Alipay();
            case "wechat": return new WeChatPay();
            default: throw new IllegalArgumentException("不支持的支付方式");
        }
    }
}

Payment payment = PaymentFactory.getPayment("alipay");
payment.pay(150);

List<Payment> payments = Arrays.asList(
    new Alipay(),
    new WeChatPay()
);
<p>for (Payment p : payments) {
p.pay(50);
}</p>

# payment.properties
alipay=com.example.Alipay
wechat=com.example.WeChatPay