【发布时间】：2022-01-19 23:14:39
【问题描述】：
我正在尝试在基于 Spring webflux 的应用程序中实现用于支付处理的策略模式方法。
我的应用程序支持多种支付方式，如卡支付、现金支付…… 此外，我们必须支持 Square & Stripe 卡支付。
模型类，
// Model interface
public interface PaymentModel {
}
// Base model with attributes needed for all payment types
public class BaseModel implements PaymentModel {
private Float amount;
private Integer userId;
}
public class SquareCardModel extends BaseModel {
private String merchantId;
private String device;
private String orderId;
}
public class StripeCardModel extends BaseModel {
private String merchantId;
private String orderId;
}
public class CashModel extends BaseModel {
private String name;
private String orderId;
}
服务类，
@Service
public interface PaymentService<T extends PaymentModel> {
Mono<ServerResponse> pay(T model);
String method();
}
@Service
public class CashPaymentService implements PaymentService<CashModel> {
private static final String PAYMENT_METHOD = "cash";
@Override
public Mono<ServerResponse> pay(CashModel model) {
// TODO Auto-generated method stub
return null;
}
@Override
public String method() {
return PAYMENT_METHOD;
}
}
@Service
public class SquarePaymentService implements PaymentService<SquareCardModel> {
private static final String PAYMENT_METHOD = "cash";
@Override
public Mono<ServerResponse> pay(SquareCardModel model) {
// TODO Auto-generated method stub
return null;
}
@Override
public String method() {
return PAYMENT_METHOD;
}
}
@Service
public class StripePaymentService implements PaymentService<StripeCardModel> {
private static final String PAYMENT_METHOD = "cash";
@Override
public Mono<ServerResponse> pay(SquareCardModel model) {
// TODO Auto-generated method stub
return null;
}
@Override
public String method() {
return PAYMENT_METHOD;
}
}
工厂类，
@Service
public class PaymentFactory<T> {
private final List<PaymentService<? extends PaymentModel>> paymentServices;
@Autowired
public PaymentFactory(List<PaymentService<? extends PaymentModel>> paymentServices) {
this.paymentServices = paymentServices;
}
public PaymentService<? extends PaymentModel> retrievePaymentService(final String paymentMethod) {
Optional<PaymentService<? extends PaymentModel>> paymentService = paymentServices.stream()
.filter(service -> service.method().equals(paymentMethod)).findFirst();
if (paymentService.isEmpty()) {
throw new IllegalArgumentException("Unsupported Payment method ");
}
return paymentService.get();
}
}
用户选择支付方式，调用到后台，
@Transactional
public Mono<ServerResponse> payBilling(ServerRequest request) {
return request.bodyToMono(PaymentDto.class).flatMap(paymentReq -> {
if (paymentReq.getPaymentType().equals("CC")) { // For Card
return processCardPayment(usr, paymentReq);
} else {
return badRequest().bodyValue("Not supported yet !");
}
});
}
private Mono<? extends ServerResponse> processCardPayment(
PaymentDto paymentReq) {
PaymentService<PaymentModel> paymentService = (PaymentService<PaymentModel>) paymentFactory
.retrievePaymentService(paymentReq.getPaymentType());
PaymentModel paymentModel = buildPaymentModel((String) paymentReq.getPaymentType(), paymentReq,
jsonMap);
return paymentService.pay(paymentModel);
}
private PaymentModel buildPaymentModel(final String paymentMethod, final PaymentDto paymentReq,
if (paymentMethod.equals("squarePayment")) {
SquareCardModel model = new SquareCardModel();
model.setAmount(paymentReq.getTotal());
model.setMerchantId(paymentReq.getMerchantid());
model.setOrderId(orderId);
return model;
}
return null;
}
问题：
- 不确定我是否使用策略模式正确实现了泛型。
- 另外，我不喜欢这里的类型转换。 （支付服务）。有没有更好的方法？
- 为什么我还需要使用 if 来创建不同的模型。
if (paymentMethod.equals("squarePayment")) {
PaymentService<PaymentModel> paymentService = (PaymentService<PaymentModel>) paymentFactory
.retrievePaymentService(paymentReq.getPaymentType());
PaymentModel paymentModel = buildPaymentModel((String) paymentReq.getPaymentType(), paymentReq,
jsonMap);
return paymentService.pay(paymentModel);
【问题讨论】：
-
你没有显示
retrievePaymentService的代码。 -
@tgdavies 抱歉打错了。它在工厂类中。
-
Float amount;?哦。不好了。没有没有。 -
@rzwitserloot 有什么建议？ BigDecimal ... 我们仅支持 2 位十进制数字，例如 1000.25 或 80.74 .... 金额不会超过 10K
-
PaymentFactory（应该命名为PaymentServiceFactory）似乎不需要有类型参数。
标签： java generics design-patterns factory strategy-pattern