1. 源代码

load->model('goodsModel','goods');
    $this->load->model('productModel','product');
    $this->load->model('goodsAttrModel','goodsAttr');
  }
  /**
   * [购物车]数据添加
   */
  public function cartAdd()
  {
    #接收购物车提交数据
    $this->info = $this->input->post();
  // $this->ajaxReturn($this->info);
    #1.验证商品库存、货品库存
    $this->checkGoodsNumber();
    #2.查询规格名称、价格
    $this->getSpecData();
    #3.组装购物车添加de数据
    $cartData = $this->setCartData();
  p(json_decode($this->input->cookie('cart'),true));
    # 一、判断是否登录
    if(!UID){
      //未登录 数据存入Cookie中
      //1:获取cookie中的购物车数据
      $cookieCartData = $this->input->cookie('cart');
      //2:判断cookie中数据是否为空
      if(empty($cookieCartData)){
        //2-1:为空则表示用户没有添加过购物车
        //2-1-1.设置Key-->生成购物车数据
        $key = $cartData['goods_id'].'-'.$cartData['product_id'];
        $cookieCart = array($key => $cartData);
        //2-1-2.设置购物车返回值(商品数量、总价)
        $this->setCartReturn(1,$cartData['goods_price']);
        //2-1-3.设置Cookie存储购物车数据
      }else{
        //2-2:不为空 表示用户添加过购物车
        //2-2-1.追加购物数据
        $cookieCart = $this->addCartData($cartData,json_decode($cookieCartData,true));
        //2-2-2.设置购物车返回值(商品数量、总价)
        $this->setCartReturn(count($cookieCart),array_sum(array_column($cookieCart, 'goods_price')));
      }
      //3:设置Cookie存储购物车数据
      setCookie('cart',json_encode($cookieCart),LEFT_TIME,'/');
    }else{
      //已登录 数据存入数据库
    }
    //返回购物车提示数据
    $this->ajaxReturn($this->msg);
  }
  /**
   * 验证商品库存
   */
  public function checkGoodsNumber()
  {
    $this->goods->map = array(
      'goods_id'     =>  $this->info['goods_id'],
      'goods_number >='  => $this->info['buy_number'],
    );
    $this->goods = $this->goods->find('goods_id,goods_name,goods_sn,goods_img,shop_price');
    if(!$this->goods){
      $this->msg['msg'] = "商品库存不足";
      $this->ajaxReturn($this->msg);
    }
    #验证货品库存
    $this->product->map = array(
      'goods_id'     =>  $this->info['goods_id'],
      'product_attr'   =>  $this->info['prod_attr'],
      'product_number >=' => $this->info['buy_number'],
    );
    $this->prodData = $this->product->find();
    if(!$this->prodData){
      $this->msg['msg'] = "货品库存不足";
      $this->ajaxReturn($this->msg);
    }
    return true;
  }
  /**
   * 组合规格名称、价格
   */
  public function getSpecData()
  {
    $this->goodsAttr->map = inToType(explode("|", $this->info['prod_attr']),'goods_attr_id');
    $goodsAttrInfo = $this->goodsAttr->select('goods_attr_value,goods_attr_price');
    $this->specData['product_attr_value'] = implode("|", array_column($goodsAttrInfo, 'goods_attr_value'));
    $this->specData['product_price'] = array_sum(array_column($goodsAttrInfo,'goods_attr_price'));
    # 返回规格信息 $this->specData
  }
  /**
   * 组装购物车添加的数组
   */
  public function setCartData()
  {
    $this->cartData = array(
      'product_id'  =>  $this->prodData['product_id'],
      'product_attr' =>  $this->prodData['product_attr'],
      'buy_number'  =>  $this->info['buy_number'],
      'goods_price'  =>  $this->info['shop_price'],
      'goods_sum'   =>  $this->info['shop_price'] * $this->info['buy_number'],
      'product_price' =>  '',
      'product_attr_value'  =>  '',
      'uid'      =>  UID,
    );
    $this->cartData = array_merge($this->cartData,$this->goods);
    #若存在规格【添加规格信息】
    if(!empty($this->info['prod_attr'])){
      $this->cartData['product_price'] = $this->specData['product_price'];
      $this->cartData['product_attr_value'] = $this->specData['product_attr_value'];
    }
    return $this->cartData;
    # 购物车 添加的总数据 $this->cartData;
  }
  /**
   * 设置购物车返回提示数据
   * @param [商品数量,总价]
   */
  public function setCartReturn($number,$prices)
  {
    $this->msg['code'] = self::STATUS_ON;
    $this->msg['data'] = array(
        'number'  =>  $number,
        'prices'  =>  $prices,
    );
  }
  /**
   * 购物车 新添加数据
   * @param [新数据,原购物车数据]
   */
  public function addCartData($newData,$oldData)
  {
    #组合Key
    $key = $newData['goods_id'].'-'.$newData['product_id'];
    // #判断购物车中是否有该商品
    if(isset($oldData[$key])){
      //1.有 合并商品数量、价格
      $oldData[$key]['buy_number'] = $oldData[$key]['buy_number'] + $newData['buy_number'];
      $oldData[$key]['goods_price'] = $newData['goods_price'];
      $oldData[$key]['goods_sum'] = $oldData[$key]['buy_number'] * $oldData[$key]['goods_price'];
    }else{
      //2.没有 追加新商品
      $oldData[$key] = $newData;
    }
    #返回购物车数据
    return $oldData;
  }
}
?>

2. 数据库

CREATE TABLE `shop_goods` (
 `goods_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
 `goods_name` varchar(255) NOT NULL,
 `type_id` int(11) DEFAULT NULL,
 PRIMARY KEY (`goods_id`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8;
CREATE TABLE `shop_product` (
 `product_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
 `goods_id` int(11) NOT NULL,
 `goods_price` decimal(10,2) NOT NULL,
 `goods_num` int(11) NOT NULL,
 `goods_sn` varchar(50) NOT NULL,
 `goods_attr_id` varchar(100) NOT NULL,
 PRIMARY KEY (`product_id`)
) ENGINE=InnoDB AUTO_INCREMENT=18 DEFAULT CHARSET=utf8;
CREATE TABLE `shop_goods_attr` (
 `goods_attr_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
 `goods_id` int(11) NOT NULL,
 `attr_id` int(11) NOT NULL,
 `attr_value` varchar(255) NOT NULL,
 PRIMARY KEY (`goods_attr_id`)
) ENGINE=InnoDB AUTO_INCREMENT=126 DEFAULT CHARSET=utf8;