策略+工厂完成支付方式选择(微信/支付宝)，简单实现

需求

传参String payType = wechat 使用微信支付
传参String payType = ali 使用支付宝支付
代码不允许出现if-else

思路

把支付当作一个行为，代码中当作一个接口，payService。2个实现类，分别是微信支付实现类WeChatPayServiceImpl，支付宝支付实现类AliPayImpl。利用多态+工厂根据支付类型获取对应的实现类

代码如下

支付接口payService

public interface PayService {
	// 下单接口
    String jsapi(Map<String,Object> map);
}

微信支付实现类WeChatPayServiceImpl

@Slf4j
@Service
@CacheConfig(cacheNames = "weChatPay")
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true, rollbackFor = Exception.class)
public class WeChatPayServiceImpl implements PayService {


    @Override
    public String jsapi(Map<String, Object> map) {
        return "微信支付";
    }
}

支付宝支付实现类AliPayImpl

@Slf4j
@Service
@CacheConfig(cacheNames = "aliPay")
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true, rollbackFor = Exception.class)
public class AliPayImpl implements PayService {

    @Override
    public String jsapi(Map<String, Object> map) {
        return "支付宝支付";
    }

}

工厂

public class PayFactory {

    private static final Map<String, PayService> PayFactoryMap = new HashMap<>();

    static {
        PayFactoryMap.put("wechat", new WeChatPayServiceImpl());
        PayFactoryMap.put("ali", new AliPayImpl());
    }

    public static PayService getPayment(String payType) {
        PayService payService = PayFactoryMap.get(payType);
        if (null == payService) throw new RuntimeException("支付类型错误");
        return payService;
    }
}

具体实现

偷懒直接在controller实现

@ApiOperation(value = "订单支付接口")
    @GetMapping("/pay")
    public ResponseEntity pay(String payType){
        PayService medalService = PayFactory.getPayment(payType);
        String jsapi = medalService.jsapi(null);
        log.info(jsapi);
        return new ResponseEntity<>(jsapi,HttpStatus.OK);
    }