m2 购物车数量太多，运行缓慢或者报错，我们可以直接通过命令行的方式直接将客户的购物车生成订单

1. 首先创建命令行，在此不多言
2. 创建代码如下

/**
     * @param $customerId  用户ID
     * @param $quoteId     购物车ID
     * @param $orderId     随意拿一个客户的历史订单ID,获取订单里面的运输方式和地址
     */
    public function createNewOrder($customerId, $quoteId, $orderId) {
        $objectManager =   \Magento\Framework\App\ObjectManager::getInstance();
        $quoteRepository = $objectManager->get(\Magento\Quote\Api\CartRepositoryInterface::class);
        $quoteManagement = $objectManager->get(\Magento\Quote\Api\CartManagementInterface::class);
        $orderRepository = $objectManager->get(\Magento\Sales\Api\OrderRepositoryInterface::class);
        $serializer = $objectManager->get(\Magento\Framework\Serialize\Serializer\Json::class);
        $order = $orderRepository->get($orderId);
        if (empty($order->getId())) {
            echo '订单不存在';
        }
        $newQuote = $quoteRepository->get($quoteId);
        $newQuote->setStoreId(2);
        $newQuote->getShippingAddress()->setCollectShippingRates(true)
            ->collectShippingRates()->setShippingMethod($order->getShippingMethod());
        $newQuote->getShippingAddress()->setShippingDescription($order->getShippingDescription());
        foreach ($newQuote->getAllVisibleItems() as $item) {
            $options = [];
            $productOptions = $item->getProduct()->getTypeInstance()->getOrderOptions($item->getProduct());
            if ($productOptions) {
                $productOptions['info_buyRequest']['options'] = $this->_prepareOptionsForRequest($item);
                $options = $productOptions;
            }
            $addOptions = $item->getOptionByCode('additional_options');
            if ($addOptions) {
                $options['additional_options'] = $serializer->unserialize($addOptions->getValue());
            }
            $item->setProductOrderOptions($options);
            $item->save();
            print_r($options);
        }
        $quoteRepository->save($newQuote);
        echo '开始创建';
        $newOrder = $quoteManagement->submit($newQuote);
        echo '成功,orderID:' . $newOrder->getId();
    }

    protected function _prepareOptionsForRequest($item)
    {
        $objectManager =   \Magento\Framework\App\ObjectManager::getInstance();
        $newInfoOptions = [];
        $optionIds = $item->getOptionByCode('option_ids');
        if ($optionIds) {
            foreach (explode(',', $optionIds->getValue()) as $optionId) {
                $option = $item->getProduct()->getOptionById($optionId);
                $optionValue = $item->getOptionByCode('option_' . $optionId)->getValue();
                $group = $objectManager->get(
                    \Magento\Catalog\Model\Product\Option::class
                )->groupFactory(
                    $option->getType()
                )->setOption(
                    $option
                )->setQuoteItem(
                    $item
                );

                $newInfoOptions[$optionId] = $group->prepareOptionValueForRequest($optionValue);
            }
        }

        return $newInfoOptions;
    }