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一、业务场景：当客户下单在指定的时间内如果没有付款，那我们需要将这笔订单取消掉，比如好的处理方法是运用延时取消，很多人首先想到的当然是crontab，这个也行，不过这里我们运用swoole的异步毫秒定时器来实现，同样也不会影响到当前程序的运行，具体可以参考：https://wiki.swoole.com/wiki/page/319.html

二、说明，order_status为1时代表客户下单确定，为2时代表客户已付款，为0时代表订单已取消(正是swoole来做的)

三、举例说明，库存表csdn_product_stock产品ID为1的产品库存数量为20，产品ID为2的库存数量为40，然后客户下单一笔产品ID1减10，产品ID2减20，所以库存表只够2次下单，例子中10秒后自动还原库存，如下图：

图解：1、第一次下完单产品ID1库存从20减到了10，产品ID2库存从40减到了20；2、第二次下完单产品ID的库存为0了，产品ID2的库存也为0了，3、第三次下单时，程序提示Out of stock；4、过了10秒钟(每个订单下单后往后推10秒)，客户两次下单，由于没有付款(csdn_order表的order_status为1)，产品1和产品2的库存被还原了(csdn_order表的order_status变为0)，客户又可以继续下单了

1、所需要sql数据库表

DROP TABLE IF EXISTS `csdn_order`;CREATE TABLE `csdn_order` ( `order_id` int(10) unsigned NOT NULL AUTO_INCREMENT, `order_amount` float(10,2) unsigned NOT NULL DEFAULT '0.00', `user_name` varchar(64) CHARACTER SET latin1 NOT NULL DEFAULT '', `order_status` tinyint(2) unsigned NOT NULL DEFAULT '0', `date_created` datetime NOT NULL, PRIMARY KEY (`order_id`)) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;DROP TABLE IF EXISTS `csdn_order_detail`;CREATE TABLE `csdn_order_detail` ( `detail_id` int(10) unsigned NOT NULL AUTO_INCREMENT, `order_id` int(10) unsigned NOT NULL, `product_id` int(10) NOT NULL, `product_price` float(10,2) NOT NULL, `product_number` smallint(4) unsigned NOT NULL DEFAULT '0', `date_created` datetime NOT NULL, PRIMARY KEY (`detail_id`), KEY `idx_order_id` (`order_id`)) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;DROP TABLE IF EXISTS `csdn_product_stock`;CREATE TABLE `csdn_product_stock` ( `auto_id` int(10) unsigned NOT NULL AUTO_INCREMENT, `product_id` int(10) NOT NULL, `product_stock_number` int(10) unsigned NOT NULL, `date_modified` datetime NOT NULL, PRIMARY KEY (`auto_id`), KEY `idx_product_id` (`product_id`)) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;INSERT INTO `csdn_product_stock` VALUES ('1', '1', '20', '2018-09-13 19:36:19');INSERT INTO `csdn_product_stock` VALUES ('2', '2', '40', '2018-09-13 19:36:19');

下面贴出来纯手工PHP，很多同学用了原生PHP，就不会运用到框架里去，其实都一样的，不要想得那么复杂就是了。只要一点就是你用多了，你就会这样觉得咯。

配置文件config.php ，这个在框架的话，基本上都是配置好了。

<?php $dbHost = "192.168.23.110";$dbUser = "root";$dbPassword = "123456";$dbName = "test";?>

swoole都是用在linux系统里的，这里的host你可以自己搭建虚拟主机，也可以网上购买属于自己的服务器

订单提交的文件order_submit.php，这里对订单生成，同时扣除库存的一系列操作

<?phprequire ("config.php");try { $pdo = new PDO("mysql:host=" . $dbHost . ";dbname=" . $dbName, $dbUser, $dbPassword, array(PDO::ATTR_PERSISTENT => true)); $pdo->setAttribute(PDO::ATTR_AUTOCOMMIT, 1); $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); $orderInfo = array( 'order_amount' => 10.92, 'user_name' => 'yusan', 'order_status' => 1, 'date_created' => 'now()', 'product_lit' => array( 0 => array( 'product_id' => 1, 'product_price' => 5.00, 'product_number' => 10, 'date_created' => 'now()' ), 1 => array( 'product_id' => 2, 'product_price' => 5.92, 'product_number' => 20, 'date_created' => 'now()' ) ) ); try{ $pdo->beginTransaction();//开启事务处理 $sql = 'insert into csdn_order (order_amount, user_name, order_status, date_created) values (:orderAmount, :userName, :orderStatus, now())'; $stmt = $pdo->prepare($sql);  $affectedRows = $stmt->execute(array(':orderAmount' => $orderInfo['order_amount'], ':userName' => $orderInfo['user_name'], ':orderStatus' => $orderInfo['order_status'])); $orderId = $pdo->lastInsertId(); if(!$affectedRows) { throw new PDOException("Failure to submit order!"); } foreach($orderInfo['product_lit'] as $productInfo) { $sqlProductDetail = 'insert into csdn_order_detail (order_id, product_id, product_price, product_number, date_created) values (:orderId, :productId, :productPrice, :productNumber, now())'; $stmtProductDetail = $pdo->prepare($sqlProductDetail);  $stmtProductDetail->execute(array(':orderId' => $orderId, ':productId' => $productInfo['product_id'], ':productPrice' => $productInfo['product_price'], ':productNumber' => $productInfo['product_number'])); $sqlCheck = "select product_stock_number from csdn_product_stock where product_id=:productId";  $stmtCheck = $pdo->prepare($sqlCheck);  $stmtCheck->execute(array(':productId' => $productInfo['product_id']));  $rowCheck = $stmtCheck->fetch(PDO::FETCH_ASSOC); if($rowCheck['product_stock_number'] < $productInfo['product_number']) { throw new PDOException("Out of stock, Failure to submit order!"); } $sqlProductStock = 'update csdn_product_stock set product_stock_number=product_stock_number-:productNumber, date_modified=now() where product_id=:productId'; $stmtProductStock = $pdo->prepare($sqlProductStock);  $stmtProductStock->execute(array(':productNumber' => $productInfo['product_number'], ':productId' => $productInfo['product_id'])); $affectedRowsProductStock = $stmtProductStock->rowCount(); //库存没有正常扣除，失败，库存表里的product_stock_number设置了为非负数 //如果库存不足时，sql异常：SQLSTATE[22003]: Numeric value out of range: 1690 BIGINT UNSIGNED value is out of range in '(`test`.`csdn_product_stock`.`product_stock_number` - 20)' if($affectedRowsProductStock <= 0) { throw new PDOException("Out of stock, Failure to submit order!"); } } echo "Successful, Order Id is：" . $orderId ."，Order Amount is：" . $orderInfo['order_amount'] . "。"; $pdo->commit();//提交事务 //exec("php order_cancel.php -a" . $orderId . " &"); pclose(popen('php order_cancel.php -a ' . $orderId . ' &', 'w')); //system("php order_cancel.php -a" . $orderId . " &