Java设计模式之策略模式案例详解

public interface Payment {
    
    String getPayType();
    
    String pay(String order);
}

@Component
public class AlipayPayment implements Payment {
    @Override
    public String getPayType() {
        return "alipay";
    }
    @Override
    public String pay(String order) {
        //调用阿里支付
        System.out.println("调用阿里支付");
        return "success";
    }
}
@Component
public class BankCardPayment implements Payment {
    @Override
    public String getPayType() {
        return "bankCard";
    }
    @Override
    public String pay(String order) {
        //调用微信支付
        System.out.println("调用银行卡支付");
        return "success";
    }
}
@Component
public class WxPayment implements Payment {
    @Override
    public String getPayType() {
        return "weixin";
    }
    @Override
    public String pay(String order) {
        //调用微信支付
        System.out.println("调用微信支付");
        return "success";
    }
}

public class PaymentFactory {
    private static final Map<String, Payment> payStrategies = new HashMap<>();
    static {
        payStrategies.put("weixin", new WxPayment());
        payStrategies.put("alipay", new AlipayPayment());
        payStrategies.put("bankCard", new BankCardPayment());
    }
    public static Payment getPayment(String payType) {
        if (payType == null) {
            throw new IllegalArgumentException("pay type is empty.");
        }
        if (!payStrategies.containsKey(payType)) {
            throw new IllegalArgumentException("pay type not supported.");
        }
        return payStrategies.get(payType);
    }
}

public class Test {
    public static void main(String[] args) {
        String payType = "weixin";
        Payment payment = PaymentFactory.getPayment(payType);
        String pay = payment.pay("");
        System.out.println(pay);
    }
}