Session简单购物车实现
2019-05-23 / JAVA / 1574 次围观 / 0 次吐槽 /显示书列表:
@WebServlet("/BookAll") public class BookAll extends HttpServlet{ @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType("text/html;charset=utf-8"); resp.getWriter().write("图书列表 <br/>"); //显示书籍列表 for(Entry<Integer, Book> entry : DBUtil.getAllBook().entrySet()) { String html = "<a href='"+req.getContextPath()+"/ShoppingCart?id="+entry.getKey()+"'>"+entry.getValue().getName()+" 点击添加购物车</a><br/>"; resp.getWriter().write(html); } resp.getWriter().write("查看购物车:" + "<a href='"+req.getContextPath()+"/ShoppingCart"+"'>购物车</a>"); } }
添加购物车和显示购物车:
@WebServlet("/ShoppingCart") public class ShoppingCart extends HttpServlet{ @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType("text/html;charset=utf-8"); //查询ID String id = req.getParameter("id"); if(id != null) { Book book = DBUtil.findBookById(Integer.parseInt(id)); //查看session HttpSession session = req.getSession(); List<Book> shoppingCart = (List<Book>)session.getAttribute("ShoppingCart"); if(shoppingCart == null) {//如果不存在,创建新列表 shoppingCart = new ArrayList<Book>(); } //添加到列表 shoppingCart.add(book); //保存至session session.setAttribute("ShoppingCart", shoppingCart); resp.getWriter().write("添加购物车成功:" + book.toString()); }else { //查看session HttpSession session = req.getSession(); List<Book> shoppingCart = (List<Book>)session.getAttribute("ShoppingCart"); if(shoppingCart == null) { resp.getWriter().write("购物车里还没有东西!"); }else { resp.getWriter().write("购物车列表:<br/>"); for(Book b : shoppingCart) { resp.getWriter().write(b + "<br/>"); } } } } }
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