商品微服务-添加购物车接口开发和方法抽取

    <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson 引入阿里巴巴cloud后自带，TODO 可以删除这个包 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.75</version>
        </dependency>

import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import net.xdclass.constant.CacheKey;
import net.xdclass.enums.BizCodeEnum;
import net.xdclass.exception.BizException;
import net.xdclass.interceptor.LoginInterceptor;
import net.xdclass.model.LoginUser;
import net.xdclass.request.CartItemRequest;
import net.xdclass.service.CartService;
import net.xdclass.service.ProductService;
import net.xdclass.vo.CartItemVO;
import net.xdclass.vo.ProductVO;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.BoundHashOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;



@Service
@Slf4j
public class CartServiceImpl implements CartService {

    @Autowired
    private ProductService productService;

    @Autowired
    private RedisTemplate redisTemplate;


    @Override
    public void addToCart(CartItemRequest cartItemRequest) {

        //商品id
        long productId = cartItemRequest.getProductId();
        //购买数量
        int buyNum = cartItemRequest.getBuyNum();

        //获取购物车
        BoundHashOperations<String, Object, Object> myCart = getMyCartOps();
        //获取Redis缓存中的商品id
        Object cacheObj = myCart.get(productId);
        String result = "";

        //看看有没有
        if (cacheObj != null) {
            result = (String) cacheObj;
        }

        if (StringUtils.isBlank(result)) {
            //不存在则新建一个商品
            CartItemVO cartItemVO = new CartItemVO();

            ProductVO productVO = productService.findDetailById(productId);
            if (productVO == null) {
                throw new BizException(BizCodeEnum.CART_FAIL);
            }

            cartItemVO.setAmount(productVO.getAmount());
            cartItemVO.setBuyNum(buyNum);
            cartItemVO.setProductId(productId);
            cartItemVO.setProductImg(productVO.getCoverImg());
            cartItemVO.setProductTitle(productVO.getTitle());
            //将对象转换为json
            myCart.put(productId, JSON.toJSONString(cartItemVO));

        } else {
            //存在商品，修改数量
            //将json转换为对象
            CartItemVO cartItem = JSON.parseObject(result, CartItemVO.class);
            cartItem.setBuyNum(cartItem.getBuyNum() + buyNum);
            myCart.put(productId, JSON.toJSONString(cartItem));
        }

    }


    /**
     * 抽取我的购物车，通用方法
     * 这个就是双重map结构
     *
     * @return
     */
    private BoundHashOperations<String, Object, Object> getMyCartOps() {
        String cartKey = getCartKey();
        return redisTemplate.boundHashOps(cartKey);
    }


    /**
     * 购物车缓存 key
     *
     * @return
     */
    private String getCartKey() {
        LoginUser loginUser = LoginInterceptor.threadLocal.get();
        String cartKey = String.format(CacheKey.CART_KEY, loginUser.getId());
        return cartKey;

    }


}