通过产品ID得到collection

You can do as following for filtering products id 10 and 12

$products->addAttributeToFilter('entity_id', array('in'=>array(10,12)));

当然这种方式的上面，必须用  ->addAttributeToSelect();


下面这种方式比较实用的，如果想按照名字排序，那么使用方法：setOrder("name","asc");如果想按照ids中的排列的顺序，那么实用   $collection->getSelect()->order("find_in_set(e.entity_id,'".implode(',',$ids)."')");  此为zf框架！

$idss = Mage::registry("idss");
$ids =  explode(",",$idss);

 //= array(3552,3553,3554,3555);
        $collection = Mage::getModel('catalog/product')->getCollection()
        ->addAttributeToSelect('*')
        ->addAttributeToFilter('entity_id',$ids);
    //    ->setOrder("name", "asc");

        $collection->getSelect()->order("find_in_set(e.entity_id,'".implode(',',$ids)."')");
       
        $this->setCollection($collection);

http://blog.csdn.net/terry_water/article/details/6592261

补充：

    Mytest_Catalog_Model_Resource_Eav_Mysql4_Product_Collection

    public function addIdFilter($productId, $exclude = false)

    第一个参数是具体的entity_id，第二个参数决定包含(in)还是排除(nin)