如何用PHP寫(xiě)一個(gè)購(gòu)物車類呢，下面我們來(lái)簡(jiǎn)單分析學(xué)習(xí)下。

代碼

namespace app\common\helper;


use app\common\model\Cart;
use app\common\model\GoodsMain;

class CartHelper
{
    protected $cart;
    protected $cartList;
    public function __construct()
    {
        $this->cart = new Cart();
        $this->cartList = array();
    }

    // 添加到購(gòu)物車
    public function push($good_main_id, $good_num)
    {
        if (!session("?user")) {
            $this->cartList = session('cartList');
            if (isset($this->cartList[$good_main_id])) {
                $this->cartList[$good_main_id] = $this->cartList[$good_main_id] + $good_num;
            } else {
                $this->cartList[$good_main_id] = $good_num;
            }
            session('cartList', $this->cartList);
        } else {
            $user = session('user');
            $cartList = $user->cart()->where('goods_main_id', '=', $good_main_id)->find();
            if ($cartList) {
                $cartList->goods_num = $cartList->goods_num + $good_num;
                $cartList->save();
            } else {
                $user->cart()->save(["goods_main_id"=>$good_main_id, "goods_num"=>$good_num]);
            }
        }
    }
    // 刪除購(gòu)物車
    public function del($good_main_id)
    {
        if (!is_array($good_main_id)) {
            $good_main_id[] = $good_main_id;
        }

        if (!session("?user")) {  // 未登錄用戶 刪除 session
            $this->cartList = session('cartList');
            foreach ($good_main_id as $id) {
                if (isset($this->cartList[$id])) {
                    unset($this->cartList[$id]);
                }
            }
            session('cartList', $this->cartList);
        } else {  // 登錄用戶  從數(shù)據(jù)庫(kù)中刪除購(gòu)物車
            Cart::where([
                ["goods_main_id","in", $good_main_id],
                ["user_id", "=", session("user.id")],
            ])->delete();
        }
    }
    // 清空購(gòu)物車
    public function clear()
    {
        if (!session("?user")) {
            session('cartList', null);
        } else {
            Cart::where([
                ["user_id", "=", session("user.id")]
            ])->delete();
        }
    }
    // 購(gòu)物車清單
    public function list()
    {
        if (session('?user')) {
            $user = session('user');
            $cartlist = $user->cart()->select();
            $list = array();
            if (!$cartlist->isEmpty()) {
                foreach ($cartlist as $k=>$v) {
                    $good = GoodsMain::find($v->goods_main_id);
                    if ($good) {
                        $temp["good"] = $good;
                        $temp["goods_num"] = $v->goods_num;
                        $list[] = $temp;
                    }
                }
            }
        } else {
            $cartlist = session('cartList');
            $list = array();
            if (!empty($cartlist)) {
                foreach ($cartlist as $k=>$v) {
                    $good = GoodsMain::find($k);
                    if ($good) {
                        $temp["good"] = $good;
                        $temp["goods_num"] = $v;
                        $list[] = $temp;
                    }
                }
            }
        }
        return $list;
    }
    // 合并購(gòu)物車  登錄前和登錄后
    public function merge()
    {
        if (!session('?user') || !session('?cartList')) {
            return false;
        }
        $user = session('user');
        $cartList = session('cartList');
        $updateArr = array();
        foreach ($cartList as $k=>$v) {
            $cart = $user->cart()->where("goods_main_id","=",$k)->find();
            if ($cart) {
                $updateArr[] = [
                    'id' => $cart->id,
                    'goods_main_id' => $k,
                    'goods_num' => $cart->goods_num + $v
                ];
            } else {
                $updateArr[] = [
                    'goods_main_id' => $k,
                    'goods_num' => $v
                ];
            }
        }
        if (!empty($updateArr)) {
            $user->cart()->saveAll($updateArr);
        }
        session('cartList', null);
    }
}

分析

添加購(gòu)物車有兩種一情況，一種是用戶已經(jīng)登錄，另一種是沒(méi)有登錄。登錄的可以直接寫(xiě)入數(shù)據(jù)庫(kù)，沒(méi)有登錄的可以用session保存。為了兼容兩種情況，所有操作都判斷了用戶是否登錄。還要考慮用戶原本購(gòu)物車?yán)镆呀?jīng)有產(chǎn)品，在沒(méi)有登錄前購(gòu)物車?yán)镆灿挟a(chǎn)品，在用戶登錄時(shí)需要進(jìn)行合并操作，上面有代碼可以參考。

保存到session的數(shù)據(jù)格式和用thinkphp6從數(shù)據(jù)庫(kù)里取出的數(shù)據(jù)格式是不一樣的，為了方便類的調(diào)用，也做了相應(yīng)的處理。

購(gòu)物車?yán)镏槐４媪水a(chǎn)品的ID和數(shù)量。

雖然很簡(jiǎn)陋，但這也是我能想出來(lái)的最好的了，一起加沒(méi)。