public void saleProps(int propID)
    {
        boolean exist = false;
        for (int i=0; i<this.getPropPackage().size(); i++)
        {
            if (this.propPackage.get(i).getID() == propID)
            {
                exist = true;
                this.propPackage.removeElementAt(i);
                break;
            }
        }
        if (exist == false)
            System.out.println("您的包裹里没有该物品");
    }