策略设计模式-下单

1、定义一个下单context类

通过这类来判断具体使用哪个实现类，可以通过一些枚举或者条件来判断

import com.alibaba.fastjson.JSON;
import com.tc.common.exception.BusinessException;
import com.tc.common.user.YjkUserDetails;
import com.tc.institution.constant.RedisConstant;
import com.tc.institution.dto.req.order.OrderConfirmReq;
import com.tc.institution.dto.req.order.OrderSubmitReq;
import com.tc.institution.dto.resp.order.OrderConfirmResp;
import com.tc.institution.dto.resp.order.OrderSubmitResp;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import javax.annotation.Resource;
import java.util.List;
import java.util.concurrent.TimeUnit;/*** TODO 4.0和4.1代码整合待完成* 1集中整合其他策略子类查询到OrderContext上下文，减少互相依赖* 2抽取已有共有方法到公共类**/
@Slf4j
@Service
public class OrderContext {@Autowiredprivate List<OrderStrategy> orderStrategyList;@Resourceprivate RedissonClient redissonClient;/*** 增加策略请维护该注释!!!* req.buyDemandOrderId 不为空走BuyDemandOrderStrategy* req.bizType = CONSULTATION_FEE(6, "问诊费订单") && req.consultationOrderId 不为空走ConsultationFeeOrderStrategy** @param req  请求参数* @param user 操作用户*/public OrderConfirmResp confirm(OrderConfirmReq req, YjkUserDetails user) {log.info("Function confirm ,req={}", req);for (OrderStrategy orderStrategy : orderStrategyList) {if (orderStrategy.confirmSupport(req) && orderStrategy.confirmCheck(req)) {OrderConfirmResp confirmResp = orderStrategy.confirm(req, user);log.info("Function confirm ,resp={}", confirmResp);return confirmResp;}}throw new BusinessException("预下单方式异常");}/*** 增加策略请维护该注释!!!* req.buyDemandOrderId 不为空走BuyDemandOrderStrategy* req.bizType = CONSULTATION_FEE(6, "问诊费订单") && req.consultationOrderId 不为空走ConsultationFeeOrderStrategy* req.bizType = CONSULTATION_EXPERT(7, "专家问诊订单") && req.consultationOrderId 不为空走ConsultationFeeOrderStrategy** @param req  请求参数* @param user 操作用户*/public OrderSubmitResp submit(OrderSubmitReq req, YjkUserDetails user) {for (OrderStrategy orderStrategy : orderStrategyList) {if (orderStrategy.submitSupport(req) && orderStrategy.submitCheck(req)) {return getOrderSubmitResp(req, user, orderStrategy);}}throw new BusinessException("预下单方式异常");}private OrderSubmitResp getOrderSubmitResp(OrderSubmitReq req, YjkUserDetails user, OrderStrategy orderStrategy) {String submitLockKey = orderStrategy.getSubmitLockKey(req, user);RLock orderLock = redissonClient.getLock(RedisConstant.ORDER_SUBMIT_LOCK_KEY + submitLockKey);try {boolean orderLockFlag = orderLock.tryLock(-1, 1, TimeUnit.MINUTES);log.info("Function submit orderLockFlag:{} param:{}", orderLockFlag, JSON.toJSONString(req));if (orderLockFlag) {OrderSubmitResp orderSubmitResp = orderStrategy.submit(req, user);log.info("Function submit param:{} result:{}", JSON.toJSONString(req), JSON.toJSONString(orderSubmitResp));return orderSubmitResp;} else {log.info("Function submit get lock fail, key:{}, now exist ...", req.getBuyDemandOrderId());throw new BusinessException("订单处理中,请勿重复多次提交");}} catch (Exception e) {log.warn("Function submit getOrderLock fail:", e);throw new BusinessException(e.getMessage());} finally {if (orderLock.isLocked() && orderLock.isHeldByCurrentThread()) {orderLock.unlock();}}}
}

2、定义一个订单策略接口，并定义公用入参

mport com.tc.institution.dto.req.order.OrderConfirmReq;
import com.tc.institution.dto.req.order.OrderSubmitReq;
import com.tc.institution.dto.resp.order.OrderConfirmResp;
import com.tc.institution.dto.resp.order.OrderSubmitResp;/*** 下单通用策略*/
public interface OrderStrategy<C,S,U> {/*** 预下单方式检验** @param req 预下单请求参数* @return*/boolean confirmSupport(OrderConfirmReq req);/*** 下单方式检验** @param req 下单请求参数* @return*/boolean submitSupport(OrderSubmitReq req);/*** 预下单参数校验** @param req 预下单请求参数* @return*/default boolean confirmCheck(OrderConfirmReq req) {return true;}/*** 下单参数校验** @param req 下单请求参数*/default boolean submitCheck(OrderSubmitReq req) {return true;}/*** 预下单** @param req  预下单请求参数* @param user 用户数据* @return*/OrderConfirmResp confirm(C req, U user);/*** 提交订单** @param req  下单请求参数* @param user 用户数据* @return*/OrderSubmitResp submit(S req, U user);/*** 获取提交订单锁** @param req  下单请求参数* @param user 用户数据* @return*/default String getSubmitLockKey(OrderSubmitReq req, U user) {return String.valueOf(req.getBuyDemandOrderId());}
}

3、定义不同类型下单策略实现类，根据业务可以有多个实现类

/*** 疫苗订单逻辑**/
@Slf4j
@Service
public class ConsultOrderStrategy implements OrderStrategy<OrderConfirmReq,OrderSubmitReq,YjkUserDetails> {}