php_错误解决_sessioin

LXY3800

　　写购物车时遇到问题，
　　Fatal error:  DangdangService::addCartItem() [<a href='dangdangservice.addcartitem'>dangdangservice.addcartitem</a>]:The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition &quot;Cart&quot; of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide a __autoload() function to load the class definition
　　查询发现;
　　$car = null;
if(empty($_SESSION['car'])){
   $uid = $_SESSION['uid'];   
   $car = DangdangService::getInstance()->createCart($uid, $bookId);
   //php 特性，对象，往session存，序列化
   $_SESSION['car'] = serialize($car);
   //$_SESSION['car'] = $car;
}else{
    $car = unserialize($_SESSION['car']);
    //$car = $_SESSION['car'];
    $_SESSION['car'] = serialize(DangdangService::getInstance()->addCartItem($car, $bookId));
    // $_SESSION['car'] = DangdangService::getInstance()->addCartItem($car, $bookId);
}
$oSmarty->assign("items",$car->getItems());
$oSmarty->display("car.html");
　　php 在session 中存取对象时要序列化  :)