jsp购物车简单的计算问题

Question

我是把要购买的东西的价格存到application的
  我是想问。。如何实现计算功能有没有人贴个代码我参考下？谢谢就差这一步了

Answer 1

建议不存到Application里，存到Sessions中或是数据库中
                  int bookId = Integer.parseInt(request.getParameter("id"));//获取要买那本书
String bookName = request.getParameter("bookName");
float bookPrice = Float.parseFloat(request.getParameter("bookPrice"));
String buy = request.getParameter("buyNum");//要买数量
int buyNum = 1;
if(buy != null && !"".equals(buy))
buyNum = Integer.parseInt(buy);

OrderDescBean odb = new OrderDescBean();//这个
odb.setBookId(bookId);
odb.setBookName(bookName);
odb.setBookPrice(bookPrice);
odb.setOrderNum(buyNum);
odb.setOrderPrice(odb.getBookPrice() * odb.getOrderNum());
Map bookCar = (Map)request.getSession().getAttribute("bookCar");
if(bookCar == null)
{
bookCar = new HashMap();
bookCar.put(bookId, odb);
}else{
bookCar.put(bookId, odb);
}
/*OrderDescBean odb = new OrderDescBean();
odb.setBookId(bookId);
odb.setBookName(bookName);
odb.setBookPrice(bookPrice);
odb.setOrderNum(1);
odb.setOrderPrice(odb.getBookPrice() * odb.getOrderNum());
Map bookCar = (Map)request.getSession().getAttribute("bookCar");
if(bookCar == null)
{
bookCar = new HashMap();
bookCar.put(bookId, odb);
}else{
OrderDescBean orderD = (OrderDescBean)bookCar.get(bookId);
if(orderD == null)
{
bookCar.put(bookId, odb);
}else{
orderD.setOrderNum(orderD.getOrderNum() + 1);
orderD.setOrderPrice(orderD.getBookPrice() * orderD.getOrderNum());
bookCar.put(bookId, orderD);
}
}*/
request.getSession().setAttribute("bookCar", bookCar);
request.getRequestDispatcher("/jsp/displayBookCar.jsp").forward(request, response);