在接口中的静态方法来获取model的实例对象

abstract class BaseModel
{ /**
* @var null
*/
protected static $_instances = Array(); /**
* 获取实例
* @return BaseModel $this
*/
public static function getInstance()
{
$className = get_called_class();
//验证实例数组内是否有该实例
if (empty(self::$_instances[$className]))
{
self::$_instances[$className] = new static();
}
//返回实例
return self::$_instances[$className];
}
}

class UserModel extends BaseModel
{ public function getUser($uid)
{
return $uid;
}
}

$uid = 1;
$res = User::getInstance()->getUser($uid);