用EJB模型实现的简单的购物车构件，可以实现商品添加，删除，查看，结算，清空功能。-EJB model implementation with a simple shopping cart component, can be achieved merchandise add, delete, view, settlement, clearing functions.

EJB实现网上购物车 有多种具体实现的功能 和异常处理-Online shopping cart EJB implementation to achieve a variety of specific functions and exception handling