我爱java系列---【redis中如何存取hash类型的值（key field value）】

@Service
public class CartServiceImpl implements CartService {

    private static final String CART="Cart_";

    @Autowired
    private RedisTemplate redisTemplate;

    @Autowired
    private SkuFeign skuFeign;

    @Autowired
    private SpuFeign spuFeign;

    /**
     * 添加购物车
     * @param skuId
     * @param num
     */
    @Override
    public void add(String skuId, Integer num,String username) {

        /**
         * 1）查询redis中的数据
         * 2）如果redis中已经有了，则追加数量，重新计算金额
         * 3）如果没有，将商品添加到缓存
         */
        OrderItem orderItem = (OrderItem) redisTemplate.boundHashOps(CART+username).get(skuId);//从redis中取值
        if (orderItem != null){
            //存在，刷新购物车
            orderItem.setNum(orderItem.getNum()+num);
            orderItem.setMoney(orderItem.getNum()*orderItem.getPrice());
            orderItem.setPayMoney(orderItem.getNum()*orderItem.getPrice());
        }else{
            //不存在，新增购物车
            Result<Sku> skuResult = skuFeign.findById(skuId);
            Sku sku = skuResult.getData();
            Spu spu = spuFeign.findByspuId(sku.getSpuId());

            //将SKU转换成OrderItem
            orderItem = this.sku2OrderItem(sku,spu,num);
        }

        //存入redis
        redisTemplate.boundHashOps(CART+username).put(skuId,orderItem);//往redis中存值


    }

    //sku转换为orderItem
    private OrderItem sku2OrderItem(Sku sku, Spu spu, Integer num) {
        OrderItem orderItem = new OrderItem();
        orderItem.setSpuId(sku.getSpuId());
        orderItem.setSkuId(sku.getId());
        orderItem.setName(sku.getName());
        orderItem.setPrice(sku.getPrice());
        orderItem.setNum(num);
        orderItem.setMoney(num*orderItem.getPrice());       //单价*数量
        orderItem.setPayMoney(num*orderItem.getPrice());    //实付金额
        orderItem.setImage(sku.getImage());
        orderItem.setWeight(sku.getWeight()*num);           //重量=单个重量*数量

        //分类ID设置
        orderItem.setCategoryId1(spu.getCategory1Id());
        orderItem.setCategoryId2(spu.getCategory2Id());
        orderItem.setCategoryId3(spu.getCategory3Id());
        return orderItem;
    }
}

redisTemplate.boundHashOps(CART+username).put(skuId,orderItem);//往redis中存值

redisTemplate.boundHashOps(CART+username).get(skuId);//从redis中取值

这里注意boundHashOps这个方法在往redis中存值的时候，在hash类型中，一个key可以对应多个多个field，一个field对应一个value。将一个对象存储为hash类型的好处之一：较于每个字段都单独存储成string类型来说，更能节约内存。