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交易下单1（未完成）

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小墨
2022-03-03 22:59:32 +08:00
parent 640105972e
commit d44db6d5be
8 changed files with 166 additions and 5 deletions
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28
README.md
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@@ -18,7 +18,7 @@
| ----------------- | --------------------- | --------------------------------------- | ---------------------------------------- | ------------------------------- |
| **Controller层** | | | | |
| Controller | controller | 类 class | | controller.UserController |
| View Object | controller/viewobject | 类 class | 将用户Model转化为可供UI使用的View Object | controller.UserController |
| View Object (VO) | controller/viewobject | 类 class | 将用户Model转化为可供UI使用的View Object | controller.UserController |
| | | | | |
| **Service层** | 转换成业务模型 | | | |
| Service | service | 接口 interface | | service.UserService |
@@ -28,7 +28,7 @@
| **Dao层** | 对数据库的映射 | | | |
| Mapper | dao | 接口 interface | | dao.UserDOMapper |
| Mapping | resources/mapping | Mapper接口实现类 | xml格式；SQL语句 | mapping/UserDOMapper.xml |
| Data Object | dataobject | 类 class | | dataobject.UserDO |
| Data Object (DO) | dataobject | 类 class | | dataobject.UserDO |
| | | | | |
| **其他** | | | | |
| response | response | | 用于处理HTTP请求返回 | response.CommonReturnType |
@@ -41,3 +41,27 @@
| BusinessException | error | CommonError接口实现类 & 继承自Exception | | error.BusinessException |
**Tips:** Model与Data Object并非完全一一对应，例如UserModel是由ServiceImpl将UserDO和UserPasswordDO组装而成的。
代码构建顺序：
1. 创建Model模型（service/model）
2. 创建数据库中数据表
3. 使用mybatis-generator生成数据库映射文件（dao ; dataobject ; resources/mapping）
4. 创建Service接口（service）
5. 创建Service接口实现Impl（service/impl）（class打上 `Service` 标注；方法上打上 `@Transactional` 标签保证是在同一事务中）
6. 思考ServiceImpl中需要哪几步，并逐步实现
> - 如果需要修改自动生成的数据库语句，先改 resources/mapping 下的xml映射SQL语句，然后修改 dao 下的DOMapper接口
>
> - 可以用 `org.springframework.beans` 包中的 `BeanUtils.copyProperties` 进行DO转Model或Model转DO（要字段和类型完全一致的字段才能拷贝，其他不对应字段的需要手动设置）
7.
8. Service返回Controller前将DO

3
src/main/java/com/cxyxiaomo/flashsale/dao/ItemStockDOMapper.java
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@@ -1,6 +1,7 @@
package com.cxyxiaomo.flashsale.dao;
import com.cxyxiaomo.flashsale.dataobject.ItemStockDO;
import org.apache.ibatis.annotations.Param;
public interface ItemStockDOMapper {
/**
@@ -52,4 +53,6 @@ public interface ItemStockDOMapper {
* @mbg.generated Thu Mar 03 13:12:13 CST 2022
*/
int updateByPrimaryKey(ItemStockDO record);
int decreaseStock(@Param("itemId") Integer itemId, @Param("amount") Integer amount);
}

9
src/main/java/com/cxyxiaomo/flashsale/error/EmBusinessError.java
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@@ -1,13 +1,16 @@
package com.cxyxiaomo.flashsale.error;
public enum EmBusinessError implements CommonError {
// 通用错误类型 00001
// 通用错误类型 10001
PARAMETER_VALIDATION_ERROR(10001, "参数不合法"),
UNKNOWN_ERROR(10002, "未知错误"),
// 10000开头为用户信息相关错误定义
// 20000开头为用户信息相关错误定义
USER_NOT_EXIST(20001, "用户不存在"),
USER_LOGIN_FAILED(20002, "用户手机号或密码不正确");
USER_LOGIN_FAILED(20002, "用户手机号或密码不正确"),
// 30000开头为交易信息错误定义
STOCK_NOT_ENOUGH(30001, "库存不足");
private EmBusinessError(int errCode, String errMsg) {
this.errCode = errCode;

2
src/main/java/com/cxyxiaomo/flashsale/service/ItemService.java
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@@ -14,4 +14,6 @@ public interface ItemService {
// 商品详情浏览
ItemModel getItemById(Integer id);
boolean decreaseStock(Integer itemId, Integer amount) throws BusinessException;
}

15
src/main/java/com/cxyxiaomo/flashsale/service/OrderService.java Normal file
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@@ -0,0 +1,15 @@
package com.cxyxiaomo.flashsale.service;
import com.cxyxiaomo.flashsale.error.BusinessException;
import com.cxyxiaomo.flashsale.service.model.OrderModel;
public interface OrderService {
/**
*
* @param userId 用户id
* @param itemId 购买商品
* @param amount 购买商品数量
* @return
*/
OrderModel createOrder(Integer userId, Integer itemId, Integer amount) throws BusinessException;
}

13
src/main/java/com/cxyxiaomo/flashsale/service/impl/ItemServiceImpl.java
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@@ -103,6 +103,19 @@ public class ItemServiceImpl implements ItemService {
return itemModel;
}
@Override
@Transactional
public boolean decreaseStock(Integer itemId, Integer amount) throws BusinessException {
int affectedRow = itemStockDOMapper.decreaseStock(itemId, amount);
if (affectedRow > 0) {
// 更新库存成功
return true;
} else {
// 更新库存失败
return false;
}
}
private ItemModel convertModelFromDataObject(ItemDO itemDO, ItemStockDO itemStockDO) {
ItemModel itemModel = new ItemModel();
BeanUtils.copyProperties(itemDO, itemModel);

95
src/main/java/com/cxyxiaomo/flashsale/service/impl/OrderServiceImpl.java Normal file
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@@ -0,0 +1,95 @@
package com.cxyxiaomo.flashsale.service.impl;
import com.cxyxiaomo.flashsale.dao.OrderDOMapper;
import com.cxyxiaomo.flashsale.dataobject.OrderDO;
import com.cxyxiaomo.flashsale.error.BusinessException;
import com.cxyxiaomo.flashsale.error.EmBusinessError;
import com.cxyxiaomo.flashsale.service.ItemService;
import com.cxyxiaomo.flashsale.service.OrderService;
import com.cxyxiaomo.flashsale.service.UserService;
import com.cxyxiaomo.flashsale.service.model.ItemModel;
import com.cxyxiaomo.flashsale.service.model.OrderModel;
import com.cxyxiaomo.flashsale.service.model.UserModel;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.math.BigDecimal;
@Service
public class OrderServiceImpl implements OrderService {
@Autowired
private ItemService itemService;
@Autowired
private UserService userService;
@Autowired
private OrderDOMapper orderDOMapper;
@Override
@Transactional
public OrderModel createOrder(Integer userId, Integer itemId, Integer amount) throws BusinessException {
// 1. 校验下单状态
// 下单的商品是否存在；用户是否合法；购买数量是否正确
ItemModel itemModel = itemService.getItemById(itemId);
if (itemModel == null) {
throw new BusinessException(EmBusinessError.PARAMETER_VALIDATION_ERROR, "商品信息不存在");
}
UserModel userModel = userService.getUserById(userId);
if (userModel == null) {
throw new BusinessException(EmBusinessError.PARAMETER_VALIDATION_ERROR, "用户信息不存在");
}
if (amount <= 0 || amount > 99) {
throw new BusinessException(EmBusinessError.PARAMETER_VALIDATION_ERROR, "数量信息不正确");
}
// 2. 落单减库存 / 支付减库存(有可能超卖)
boolean result = itemService.decreaseStock(itemId, amount);
if (!result) {
throw new BusinessException(EmBusinessError.STOCK_NOT_ENOUGH);
}
// 3. 订单入库
OrderModel orderModel = new OrderModel();
orderModel.setUserId(userId);
orderModel.setItemId(itemId);
orderModel.setAmount(amount);
orderModel.setItemPrice(itemModel.getPrice());
orderModel.setOrderPrice(itemModel.getPrice().multiply(new BigDecimal(amount)));
// 生成交易流水号，订单号
OrderDO orderDO = convertFromOrderModel(orderModel);
orderDOMapper.insertSelective(orderDO);
// 4. 返回前端
return null;
}
private OrderDO convertFromOrderModel(OrderModel orderModel) {
if (orderModel == null) {
return null;
}
OrderDO orderDO = new OrderDO();
BeanUtils.copyProperties(orderModel, orderDO);
return orderDO;
}
// 生成交易流水号，订单号
private String generateOderNo(){
// 订单号为16位
// 前8位为时间信息（年月日）
// 中间6位为自增序列
// 最后2位为分库分表位
}
}

6
src/main/resources/mapping/ItemStockDOMapper.xml
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@@ -114,4 +114,10 @@
from item_stock
where item_id = #{itemId,jdbcType=INTEGER}
</select>
<update id="decreaseStock">
update item_stock
set stock = stock - #{amount},
item_id = #{itemId}
where item_id = #{itemId} and stock >= #{amount}
</update>
</mapper>