一.查看購物車

查看購物車使用get請求。我們要查看當前用戶的購物車，就要獲取當前用戶的userId字段進行條件查詢。因為在用戶登錄時就已經將userId封裝在token中了，因此我們只需要解析token獲取userId即可，不需要前端再傳入參數了。

Controller層

package com.sky.controller.user;import com.sky.context.BaseContext;
import com.sky.dto.ShoppingCartDTO;
import com.sky.entity.ShoppingCart;
import com.sky.result.Result;
import com.sky.service.ShoppingCartService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;import java.util.List;@RestController
@RequestMapping("/user/shoppingCart")
@Slf4j
@Api(tags = "購物車相關接口")
public class ShoppingCartController {@Autowiredprivate ShoppingCartService shoppingCartService;/*** 添加購物車* @param shoppingCartDTO* @return*/@ApiOperation("添加購物車")@PostMapping("/add")public Result add(@RequestBody ShoppingCartDTO shoppingCartDTO) {log.info("向購物車中添加菜品或套餐：{}",shoppingCartDTO);shoppingCartService.add(shoppingCartDTO);return Result.success();}/*** 查看購物車* @return*/@GetMapping("/list")@ApiOperation("查看購物車")public Result<List<ShoppingCart>> list() {log.info("查看購物車：{}", BaseContext.getCurrentId());List<ShoppingCart> list = shoppingCartService.showShoppingCart();return Result.success(list);}
}

返回一個含有當前用戶所有購物車信息的列表，列表的元素為購物車對象ShoppingCart。

Service層

接口

package com.sky.service;import com.sky.dto.ShoppingCartDTO;
import com.sky.entity.ShoppingCart;
import org.springframework.stereotype.Service;import java.util.List;@Service
public interface ShoppingCartService {/*** 添加購物車* @param shoppingCartDTO*/void add(ShoppingCartDTO shoppingCartDTO);/*** 查查看購物車* @return*/List<ShoppingCart> showShoppingCart();
}

實現類

package com.sky.service.impl;import com.sky.context.BaseContext;
import com.sky.dto.ShoppingCartDTO;
import com.sky.entity.Dish;
import com.sky.entity.Setmeal;
import com.sky.entity.ShoppingCart;
import com.sky.mapper.DishMapper;
import com.sky.mapper.SetmealMapper;
import com.sky.mapper.ShoppingCartMapper;
import com.sky.service.ShoppingCartService;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.time.LocalDateTime;
import java.util.List;@Service
public class ShoppingCartServiceImpl implements ShoppingCartService {@Autowiredprivate ShoppingCartMapper shoppingCartMapper;@Autowiredprivate DishMapper dishMapper;@Autowiredprivate SetmealMapper setmealMapper;/*** 添加購物車* @param shoppingCartDTO*/@Overridepublic void add(ShoppingCartDTO shoppingCartDTO) {// 首先判斷這次添加購物車的操作加入的菜品或套餐是否已經存在，如果存在就把份數+1，如果不存在就新增ShoppingCart shoppingCart = new ShoppingCart();BeanUtils.copyProperties(shoppingCartDTO,shoppingCart);Long userId = BaseContext.getCurrentId();shoppingCart.setUserId(userId);// 1.首先查詢該菜品或套餐在數據庫中是否存在List<ShoppingCart> list = shoppingCartMapper.list(shoppingCart);    // 每次添加的要么是菜品，要么是套餐。且如果重復添加只會增加份數而不會新增一條數據，因此每次查詢要么為空，要么查詢出1條數據if (list != null && list.size() > 0) {      // 已存在，數量+1ShoppingCart cart = list.get(0);    // 將已存在的購物車對象取出cart.setNumber(cart.getNumber() + 1);   // 并將其菜品/套餐數量+1shoppingCartMapper.updateNumberById(cart);      // 通過id更新} else {// 2.不存在，先判斷是套餐還是菜品，因為套餐和菜品在購物車中所需要的屬性是不一樣的Long dishId = shoppingCartDTO.getDishId();if (dishId != null) {// 3.如果是菜品，那么從菜品數據庫中查找并將對應屬性賦值給購物車對象Dish dish = dishMapper.getById(dishId);shoppingCart.setName(dish.getName());shoppingCart.setImage(dish.getImage());shoppingCart.setAmount(dish.getPrice());} else {// 4.如果是套餐，那么從套餐數據庫中查找并將對應屬性賦值給購物車對象Long setmealId = shoppingCartDTO.getSetmealId();Setmeal setmeal = setmealMapper.getById(setmealId);shoppingCart.setName(setmeal.getName());shoppingCart.setImage(setmeal.getImage());shoppingCart.setAmount(setmeal.getPrice());}// 5.將新增的菜品/套餐加入數據庫中shoppingCart.setNumber(1);shoppingCart.setCreateTime(LocalDateTime.now());shoppingCartMapper.insert(shoppingCart);}}/*** 查看購物車* @return*/@Overridepublic List<ShoppingCart> showShoppingCart() {Long userId = BaseContext.getCurrentId();ShoppingCart shoppingCart = ShoppingCart.builder().userId(userId).build();List<ShoppingCart> list = shoppingCartMapper.list(shoppingCart);return list;}
}

我們要根據userId來篩選要查看哪個用戶的購物車，因此要通過token令牌獲得userId，然后構建shoppingCart對象并將該屬性賦值，最后通過數據庫進行查找符合該用戶的購物車列表。

Mapper層

接口

package com.sky.mapper;import com.sky.dto.ShoppingCartDTO;
import com.sky.entity.ShoppingCart;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Update;import java.util.List;@Mapper
public interface ShoppingCartMapper {/*** 查詢菜品/套餐是否存在* @param shoppingCart* @return*/List<ShoppingCart> list(ShoppingCart shoppingCart);/*** 更新購物車中套餐/菜品份數* @param shoppingCart*/@Update("update shopping_cart set number = #{number} where id = #{id}")void updateNumberById(ShoppingCart shoppingCart);/*** 向購物車中加入菜品/套餐* @param shoppingCart*/@Insert("insert into shopping_cart(name, image, user_id, dish_id, setmeal_id, dish_flavor, number, amount, create_time) " +"VALUES (#{name}, #{image}, #{userId}, #{dishId}, #{setmealId}, #{dishFlavor}, #{number}, #{amount},#{createTime})")void insert(ShoppingCart shoppingCart);
}

XML映射文件

只有userId，根據userId查詢即可。

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.sky.mapper.ShoppingCartMapper"><select id = "list" resultType="com.sky.entity.ShoppingCart">select * from shopping_cart<where><if test="userId != null">and user_id = #{userId}</if><if test="dishId != null">and dish_id = #{dishId}</if><if test="setmealId != null">and setmeal_id = #{setmealId}</if><if test="dishFlavor != null">and dish_flavor = #{dishFlavor}</if></where></select>
</mapper>

成功?