JavaWeb书城项目-购物车

 

 

 

 

 

重定向到首页：resp.sendRedirect(req.getContextPath());

重定向到当前页：req.getHeader("Referer")

 

public class CartServlet extends BaseServlet{
    private BookService bookService = new BookServiceImpl();
    
    //更新商品数量
    protected void updateCount(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取请求的参数 商品编号  商品商量
        int id = WebUtils.parseInt(req.getParameter("id"), 0);
        int count = WebUtils.parseInt(req.getParameter("count"), 0);
        //获取cart购物车对象
        Cart cart = (Cart)req.getSession().getAttribute("cart");
        
        if(cart != null) {
            //修改商品数量
            cart.update(id, count);
            //重定向回修改页面
            resp.sendRedirect(req.getHeader("Referer"));
        }
        
    }
    
    //清空购物车
    protected void clear(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取购物车对象
        Cart cart = (Cart)req.getSession().getAttribute("cart");
        if(cart != null) {
            //清空购物车
            cart.clear();
            //重定向回清空按钮页面
            resp.sendRedirect(req.getHeader("Referer"));
        }
        
    }
    
    //删除商品项
    protected void deleteItem(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        int id = WebUtils.parseInt(req.getParameter("id"), 0);
        Cart cart = (Cart)req.getSession().getAttribute("cart");
        if(cart != null) {
            //删除指定项
            cart.deleteItem(id);
            //重定向回删除页面
            resp.sendRedirect(req.getHeader("Referer"));
        }
    }
        
    
    //加入购物车
    protected void addItem(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        
        
        //获取请求的参数：商品编号
        int id = WebUtils.parseInt(req.getParameter("id"), 0);
        //调用bookService.queryBookById(id):Book得到商品图书的信息
        Book book = bookService.queryBookById(id);
        //把图书信息转化成为cartItem商品项
        CartItem cartItem = new CartItem(book.getId(),book.getName(),1,book.getPrice(),book.getPrice());
        //调用Cart.addItem(CartItem)添加商品项
        Cart cart = (Cart)req.getSession().getAttribute("cart");
        if(cart == null) {
            cart = new Cart();
            req.getSession().setAttribute("cart", cart);
        }
        cart.addItem(cartItem);
        System.out.println(cart);
        //重定向回商品列表页面
        System.out.println("请求头Referer的值：" + req.getHeader("Referer"));
        resp.sendRedirect(req.getHeader("Referer"));
        req.getSession().setAttribute("lastName", cartItem.getName());
    }

}