購物車雛形

寫一個簡單的購物車模塊，不提供修改數量。

Servlet如下：

public   class  InputCart  extends  HttpServlet {

    Book book  =   null ;　 // bean組件
    Map map = null ;
    RequestDispatcher rd  =   null ;
    HttpSession session  =   null ;
    String isbn = null ;
    BookDAO bookdao  =   new  BookDAO();
     public   void  doGet(HttpServletRequest request, HttpServletResponse response)
             throws  ServletException, IOException {

         this .doPost(request, response);
    }

     public   void  doPost(HttpServletRequest request, HttpServletResponse response)
             throws  ServletException, IOException {

        response.setContentType( " text/html;charset=gb2312 " );
        session  =  request.getSession();
        String shopping = request.getParameter( " shopping " ); // 因為當初考慮到用戶會做到修改商品數量，因為用一個Session對象判斷用戶所進行的操作
    
         // 判断客户端是否是在进行购物
         if ( " add " .equals(shopping)) {
            isbn = request.getParameter( " isbn " ); // 獲取隱藏表單域傳遞過來的值
            book = bookdao.queryByISBN(isbn);  // 拿到当前isbn对应的商品信息 
             if (session.getAttribute( " MyCart " ) != null ) {  // 判断购物车是否存在商品
                map = (HashMap)session.getAttribute( " MyCart " );
            }  else  {
                map = new  HashMap();
            }
            map.put(isbn, book);
            session.setAttribute( " MyCart " , map);
            rd = request.getRequestDispatcher( " displayBook.jsp " );
            rd.forward(request, response);
            
        } 
        

        
    }

}

JSP頁面：

  <%
           Map map = (HashMap)session.getAttribute( " MyCart " );
           Book book = null ;
           Object[] obj = null ; // 此數組為拿到Map的Key對象
 
     %>
   < body >
    < table border = " 2 "  width = " 480 " >
     < tr >
         < th  class = " tdtitle " >< font size = 4 > ISBN </ font ></ th >
         < th  class = " tdtitle " >< font size = 4 > 書名 </ font ></ th >
         < th  class = " tdtitle " >< font size = 4 > 圖片介紹 </ font ></ th >
         < th  class = " tdtitle " >< font size = 4 > 價格 </ font ></ th >
  
     </ tr >
    
     <%
         if (map != null ) {
            Set key = map.keySet();
               obj = key.toArray();
             for ( int  i = 0 ;i < obj.length;i ++ ) {
                book = (Book)map.get(obj[i]);
                
            
         %>
             < tr >
                 < td  class = " tdl " ><%= book.getIsbn()  %></ td >
                 < td  class = " tdl " ><%= book.getTitle()  %></ td >
                 < td  class = " tdl " >< img src = " /store/images/<%=book.getImageFile() %>  "  width = " 90 "  height = " 80 " /></ td >
                 < td  class = " tdl " ><%= book.getPrice()  %></ td >
             </ tr >
            
         <%
            }
        }  else  {

         %>
         < tr >
             < td  class = " tdl " >< font color = " red "   > 当前购物车没有物品！ </ font ></ td >
         </ tr >
     <%
        }
     %>

OK,簡單的購物車雛形寫好了。