Java-springboot生鲜电商项目（五）购物车模块

购物车功能

1. 添加商品到购物车
2. 全选和全不选
3. 增加数量

涉及到的接口，购物车模块（都是前台的）

1. 购物车列表
2. 添加商品到购物车
3. 更新购物车某个商品的数量
4. 删除购物车的某个商品
5. 选中/不选中购物车的某个商品
6. 全选/全不选购物车的某个商品

业务流程

1. 判断商品是否存在，提示用户
2. 商品是否在购物车，添加商品和追加商品

总结

1. mybatis返回非标准对象，后期计算单样商品的总价
2. 添加商品到购物车时，根据是否已经存在该商品，有不同逻辑

常见错误

1. 不做越权判断

（一）购物车列表

dao

List<CartVO> selectList(@Param("userId") Integer userId);

mapper

  <select id="selectList" resultType="com.hyb.mall.model.vo.CartVO" parameterType="java.lang.Integer">selectc.id as id,p.id as productId,c.user_id as userId,c.quantity as quantity,c.selected as selected,p.price as price,p.name as productName,p.image as productImagefrom imooc_mall_cart cleft join imooc_mall_product p on p.id = c.product_idwhere c.user_id =#{userId}and p.status = 1</select>

service

    @Overridepublic List<CartVO> list(Integer userId) {List<CartVO> cartVOS = cartMapper.selectList(userId);//计算总价for (int i = 0; i < cartVOS.size(); i++) {CartVO cartVO = cartVOS.get(i);cartVO.setTotalPrice(cartVO.getPrice() * cartVO.getQuantity());}return cartVOS;}

（二）添加商品到购物车

对用户的过滤器开发：因为购物车的功能是用户的行为操作，所以在添加商品到购物车的时候，先判断是否是用户，可以借鉴管理员过滤器的开发

filter包中创建UserFilter

package com.hyb.mall.filter;
import com.hyb.mall.common.Constant;
import com.hyb.mall.model.pojo.User;
import com.hyb.mall.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.io.PrintWriter;/*** 描述：用户校验过滤器* 登录后做更深层的校验，可以拿到用户信息*/
public class UserFilter implements Filter {//登录后，能将用户信息保存下来public static User currentUser;@Autowiredprivate UserService userService;@Overridepublic void init(FilterConfig filterConfig) throws ServletException {}@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {HttpServletRequest request = (HttpServletRequest) servletRequest;HttpSession session = request.getSession();//1.获取session中的用户currentUser = (User) session.getAttribute(Constant.HYB_MALL_USER);//2.判断当前用户是否为空，为空则需要登录if (currentUser == null) {PrintWriter out = new HttpServletResponseWrapper((HttpServletResponse)servletResponse).getWriter();out.write("{\n" +"    \"status\": 10007,\n" +"    \"msg\": \"NEED_LOGIN\",\n" +"    \"data\": null\n" +"}");out.flush();out.close();return;}//3.通过用户校验filterChain.doFilter(servletRequest,servletResponse);}@Overridepublic void destroy() {}
}

对过滤器进行config配置

package com.hyb.mall.config;import com.hyb.mall.filter.AdminFilter;
import com.hyb.mall.filter.UserFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;/*** 描述：用户过滤器的配置*/
@Configuration
public class UserFilterConfig {@Beanpublic UserFilter userFilter(){return new UserFilter();}//将整个filter放到整个链路中去@Bean(name = "userFilterConf") //设置的名字不能和类名一样不然会有冲突public FilterRegistrationBean adminFilterConfig(){FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();filterRegistrationBean.setFilter(userFilter());//设置拦截的URLfilterRegistrationBean.addUrlPatterns("/cart/*");filterRegistrationBean.addUrlPatterns("/order/*");//给过滤器配置设置名字，以便于区分不同的名字filterRegistrationBean.setName("UserFilterConfig");return filterRegistrationBean;}
}

coding到这里，我发现有个小小的笔误，我在controller中@PostMapping("")注解中，映射的地址开头有些有“/”有些没有，然后我进行统一处理，全加上了，重新测试接口，到没有发现出bug。

在MallExceptionEnum中加入异常处理

NOT_SALE(10016,"商品状态不可售"),
NOT_ENOUGH(10016,"商品库存不足"),

在common常量类中设置商品上下架以及购物车选中状态

    /*** 增加商品的上下架状态*/public interface SaleStatus{int NOT_SALE = 0;//商品的下架状态int SALE = 1;//商品的上架状态}/*** 购物车是否选中状态*/public interface Cart{int UN_CHCKED = 0;//购物车未选中int CHCKED = 1;//购物车选中}

cartDAO

 Cart selectCartByUserIdAndProduct(@Param("userId") Integer userId,@Param("productId") Integer productId);

cart mapper

  <select id="selectCartByUserIdAndProduct" resultMap="BaseResultMap" parameterType="map">select<include refid="Base_Column_List"/>from imooc_mall_cartwhere user_id = #{userId}and product_id = #{productId}</select>

service

package com.hyb.mall.service.impl;import com.hyb.mall.common.Constant;
import com.hyb.mall.exception.MallException;
import com.hyb.mall.exception.MallExceptionEnum;
import com.hyb.mall.model.dao.CartMapper;
import com.hyb.mall.model.dao.ProductMapper;
import com.hyb.mall.model.pojo.Cart;
import com.hyb.mall.model.pojo.Product;
import com.hyb.mall.model.vo.CartVO;
import com.hyb.mall.service.CartSrvice;
import io.swagger.models.auth.In;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;/*** 描述：购物车service实现类*/
@Service
public class CartSrviceImpl implements CartSrvice {@AutowiredProductMapper productMapper;@AutowiredCartMapper cartMapper;@Overridepublic List<CartVO> add(Integer userId, Integer productId, Integer count){validProduct(productId,count);Cart cart = cartMapper.selectCartByUserIdAndProduct(userId, productId);//判断查出来的cart是不是为空if (cart == null) {//这个商品之前不再购物车，需要新增一个记录cart = new Cart();cart.setProductId(productId);cart.setUserId(userId);cart.setQuantity(count);cart.setSelected(Constant.Cart.CHCKED);cartMapper.insertSelective(cart);}else {//这个商品已经在购物车里了，则数量相加count = cart.getQuantity() +count;Cart cartNew = new Cart();cartNew.setQuantity(count);cartNew.setId(cart.getId());cartNew.setProductId(cart.getProductId());cartNew.setUserId(cart.getUserId());cartNew.setSelected(Constant.Cart.CHCKED);cartMapper.updateByPrimaryKeySelective(cartNew);}return this.list(userId);}//验证添加是不是合法的private void validProduct(Integer productId, Integer count) {Product product = productMapper.selectByPrimaryKey(productId);//判断商品是否存在，商品是否上架if (product == null  || product.getStatus().equals(Constant.SaleStatus.NOT_SALE)) {throw new MallException(MallExceptionEnum.NOT_SALE);}//判断商品库存if (count > product.getStock()){throw new MallException(MallExceptionEnum.NOT_ENOUGH);}}}

controller

package com.hyb.mall.controller;import com.hyb.mall.common.ApiRestResponse;
import com.hyb.mall.filter.UserFilter;
import com.hyb.mall.service.CartSrvice;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;/*** 描述：购物车controller*/
@RestController
@RequestMapping("/cart")
public class CartController {@AutowiredCartSrvice cartSrvice;@ApiOperation("添加商品到购物车")@PostMapping("/add")public ApiRestResponse add(@RequestParam Integer productId,@RequestParam Integer count){List<CartVO> cartVOList = cartSrvice.add(UserFilter.currentUser.getId(), productId, count);return ApiRestResponse.success(cartVOList);}
}

使用postman添加商品到购物车在查询商品列表

（三）更新购物车接口

service

    //更新购物车@Overridepublic List<CartVO> update(Integer userId, Integer productId, Integer count) {validProduct(productId, count);Cart cart = cartMapper.selectCartByUserIdAndProduct(userId, productId);//判断查出来的cart是不是为空if (cart == null) {//这个商品之前不再购物车，无法更新throw new MallException(MallExceptionEnum.UPDATE_FAILED);} else {//这个商品已经在购物车里了，则更新数量Cart cartNew = new Cart();cartNew.setQuantity(count);cartNew.setId(cart.getId());cartNew.setProductId(cart.getProductId());cartNew.setUserId(cart.getUserId());cartNew.setSelected(Constant.Cart.CHCKED);cartMapper.updateByPrimaryKeySelective(cartNew);}return this.list(userId);}

    @ApiOperation("更新购物车")@PostMapping("/update")public ApiRestResponse update(@RequestParam Integer productId,@RequestParam Integer count) {List<CartVO> cartVOList = cartSrvice.update(UserFilter.currentUser.getId(), productId, count);return ApiRestResponse.success(cartVOList);}

（四）删除购物车接口

service

    //删除购物车商品@Overridepublic List<CartVO> delete(Integer userId, Integer productId) {Cart cart = cartMapper.selectCartByUserIdAndProduct(userId, productId);//判断查出来的cart是不是为空if (cart == null) {//这个商品之前不再购物车，无法删除throw new MallException(MallExceptionEnum.DELETE_FAILE);} else {//这个商品已经在购物车里了，则可以删除cartMapper.deleteByPrimaryKey(cart.getId());}return this.list(userId);}

controller

    @ApiOperation("删除购物车")@PostMapping("/delete")public ApiRestResponse delete(@RequestParam Integer productId) {//不能传入userID和cartID，防止黑客攻击List<CartVO> cartVOList = cartSrvice.delete(UserFilter.currentUser.getId(), productId);return ApiRestResponse.success(cartVOList);}

postman测试

（五）单选和反选购物车商品

dao

    Integer selectOrNot(@Param("userId") Integer userId,@Param("productId") Integer productId,@Param("selected") Integer selected);

mapper

  <update id="selectOrNot" parameterType="map">update imooc_mall_cartset selected = #{selected}where user_id = #{userId}<if test="productId !=null">and product_id = #{productId}</if></update>

service

    //单选和反选购物车的商品@Overridepublic List<CartVO> selectOrNot(Integer userId, Integer productId, Integer selected){//将购物车查询出来Cart cart = cartMapper.selectCartByUserIdAndProduct(userId, productId);//判断查出来的cart是不是为空if (cart == null) {//这个商品之前不再购物车，无法更新throw new MallException(MallExceptionEnum.UPDATE_FAILED);} else {//这个商品已经在购物车里了，则可以删除cartMapper.selectOrNot(userId,productId,selected);}return this.list(userId);}

controller

    @ApiOperation("单选和反选购物车的某商品")@PostMapping("/select")public ApiRestResponse select(@RequestParam Integer productId,@RequestParam Integer selected) {//不能传入userID和cartID，防止黑客攻击List<CartVO> cartVOList = cartSrvice.selectOrNot(UserFilter.currentUser.getId(), productId,selected);return ApiRestResponse.success(cartVOList);}

（六）全选和全不选购物车商品

service:不用谢productId，这样就能将所有的购物车商品选中，将全部查询出来

    //全选和全不选购物车商品@Overridepublic List<CartVO> selectAllOrNot(Integer userId, Integer selected) {//改变选中状态cartMapper.selectOrNot(userId, null, selected);return this.list(userId);}

controller

    @ApiOperation("全选和全不选购物车商品")@PostMapping("/selectAll")public ApiRestResponse selectAll(@RequestParam Integer productId,@RequestParam Integer selected) {//不能传入userID和cartID，防止黑客攻击List<CartVO> cartVOList = cartSrvice.selectAllOrNot(UserFilter.currentUser.getId(),selected);return ApiRestResponse.success(cartVOList);}

postman