遇到一些问题,求解

org.apache.jasper.JasperException: An exception occurred processing JSP page /QueryOrder1.jsp at line 71

68:  
69: <%Cart cart = (Cart)session.getAttribute("cart"); 
70: double totalMoney = 0.0;
71: Iterator it = cart.getItems().iterator();
72: while(it.hasNext()){
73: SalesItem item = (SalesItem)it.next();
74: Product p = item.getProductId();


两台机器 一台能运行成功,另一台出现如上错误,求解

cart.getItems()==null

高手啊 这么复杂

试试：
Iterator it =null
it=cart.getItems().iterator();