Question

用servlet做购物车

请问一下用servlet做一个简单的购物车该怎样实现？

Answer 1

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { HttpSession session = request.getSession(false);
RequestDispatcher dispatcher; // 如果session不存在，转向 /books.jsp
if (session == null) {
dispatcher = request.getRequestDispatcher("/books.jsp");
dispatcher.forward(request, response);
} // 取出购物车和添加的书籍
Map cart = (Map) session.getAttribute("cart");
BookBean book = (BookBean) session.getAttribute("bookToAdd"); // 如果购物车不存在，创建购物车
if (cart == null) {
cart = new HashMap(); // 将购物车存入session之中
session.setAttribute("cart", cart);
} // 判断书籍是否在购物车中
CartItemBean cartItem = (CartItemBean) cart.get(book.getISBN()); // 如果书籍在购物车中，更新其数量.
// 否则，创建一个条目到Map中.
if (cartItem != null)
cartItem.setQuantity(cartItem.getQuantity() + 1);
else
cart.put(book.getISBN(), new CartItemBean(book, 1)); // 转向viewCart.jsp显示购物车
dispatcher = request.getRequestDispatcher("/viewCart.jsp");
dispatcher.forward(request, response);
}