使用cookies查询商品详情

易买网项目完工，把一些新知识记录下来，以便以后查阅，也方便他人借阅。介绍使用cookies查询商品详情。

第一步：建立商品实体类。

第二步：连接Oracle数据库。

第三步：使用三层架构。

效果图如下：

当我看中新疆牛肉干，商品点击时，进入查看商品详情页。

商品详情页：

核心代码如下：

 <%
    //创建商品业务逻辑对象
    productBiz prodctbiz = new productBizImpl();

List<easybuy_product> productlist = prodctbiz.findproductList();
 request.setAttribute("productlist",product);
%>//EL表达式

核心架包<%@taglib uri="http://java.sun.com/jsp/jstl/core"  prefix="c"%>//EL表达式：
<c:forEach var="news" items="${requestScope.productlist}" >

                 <li class="ck">
                    <dl>
                        <dt><a href="addcookie?id=${news.ep_id}"><img src="${news.ep_file_name}" /></a></dt>
                        <dd class="title"><a href="addcookie?id=${news.ep_id}">${news.ep_name}</a></dd>
                        <dd class="price">￥${news.ep_price}.00</dd>
                    </dl>

                    </li>

                    </c:forEach>
        

第二步：在Servlet创建addcookie.java页面,获取商品id：（注意：必须在web.xml写入）

        <!--商品id存在cookies-->
    <servlet>
    <servlet-name>addcookie</servlet-name>
    <servlet-class>Servlet.addcookie</servlet-class>
    </servlet>

  <!-- 映射servlet -->
  <servlet-mapping>
      <servlet-name>addcookie</servlet-name>
      <url-pattern>/addcookie</url-pattern>
  </servlet-mapping>

package Servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class addcookie extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public addcookie() {
        super();
    }

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

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

            doPost(request, response);
    }

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

        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        request.setCharacterEncoding("utf-8");
         //获取商品id
        String id = request.getParameter("id");
        //转发的页面
        response.setHeader("refresh", "0;url=/yimaiWang/product-view.jsp?id="+id);

        Cookie[] cookies = request.getCookies();

        String visitlist = null;
        if (cookies != null) {
            for (Cookie cookie : cookies) {
                if (cookie.getName().equals("visitlist")) {
                    visitlist = cookie.getValue();
                    break;
                }
            }
            if (visitlist == null) {

                Cookie cookie = new Cookie("visitlist", id);
                cookie.setMaxAge(180);
                response.addCookie(cookie);

            } else {

                String[] existIds = visitlist.split(",");
                for (String exsitId : existIds) {
                    if (exsitId.equals(id)) {

                        return;
                    }
                }

                Cookie cookie = new Cookie("visitlist", visitlist + "," + id);
                cookie.setMaxAge(180);
                response.addCookie(cookie);

            }
        } else {

            Cookie cookie = new Cookie("visitlist", id);
            cookie.setMaxAge(180);
            response.addCookie(cookie);

        }
    }

}

第三步：跳转商品详情页product-view.jsp(这俩个查询语句不同，一个是查询商品id，一个是商品List集合)

public easybuy_product findProductForid(int id) {
    con=this.getConnection();
    int i =id;
    String sql = "select * from easybuy_product where ep_id =?";

    easybuy_product pd = new easybuy_product();

    try
    {
        st=con.prepareStatement(sql);
        st.setInt(1,id);
        rs=st.executeQuery();    

        while(rs.next())
        {

            pd.setEp_id(rs.getInt(1));
            pd.setEp_name(rs.getString(2));
            pd.setEp_description(rs.getString(3));
            pd.setEp_price(rs.getInt(4));
            pd.setEp_stock(rs.getInt(5));
            pd.setEpc_id(rs.getInt(6));
            pd.setEpc_child_id(rs.getInt(7));
            pd.setEp_file_name(rs.getString(8));
        }
    } catch (SQLException e)
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return null;
    }finally{
        this.ShiFang(rs, st, con);

    }

    return pd;
}
}

public List<easybuy_product> product(String id) {
    List<easybuy_product> listproduct=new ArrayList<easybuy_product>();
    // TODO Auto-generated method stub

    con = this.getConnection();

    String sql="select * from easybuy_product where ep_id=?";
    try {
        st=con.prepareStatement(sql);
        st.setString(1,id);
        rs=st.executeQuery();
        while(rs.next()){
            easybuy_product product = new easybuy_product();
            product.setEp_id(rs.getInt(1));
            product.setEp_name(rs.getString(2));
            product.setEp_description(rs.getString(3));
            product.setEp_price(rs.getInt(4));
            product.setEp_stock(rs.getInt(5));
            product.setEpc_id(rs.getInt(6));
            product.setEpc_child_id(rs.getInt(7));
            product.setEp_file_name(rs.getString(8));

            listproduct.add(product);
        }
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();

        this.ShiFang(rs, st, con);
    }

    return listproduct;
}

<%
//获取商品id
int id = Integer.parseInt(request.getParameter("id"));
productBiz bizvoid = new productBizImpl();
easybuy_product shop = bizvoid.findProductForid(id);
request.setAttribute("shop",shop);
%>

<%
     //获取商品id
request.setCharacterEncoding("utf-8");
String a = request.getParameter("id");
%>
 <%

    //创建商品信息业务逻辑对象
  productBiz productbiz = new productBizImpl();

 List<easybuy_product> list =productbiz.product(a);
  request.setAttribute("list",list);

  %>
    <div id="product" class="main">
     <c:forEach var="product" items="${requestScope.list}" >
        <h1><%=shop.getEp_name() %></h1>
            </c:forEach>
        <div class="infos">
             <c:forEach var="product" items="${requestScope.list}" >
            <div class="thumb"><img src="${product.ep_file_name}" width="300px" /></div>
            <div class="buy">
            <p>商品描述：<span class="price">${product.ep_description}</span></p>
                <p>商城价：<span class="price">￥${product.ep_price}.00</span></p>
           <c:if test="${product.ep_stock==null}">
                      <p class="w1 c">缺货</p>
                            </c:if>
                   <c:if test="${product.ep_stock!=null}">
                      <p class="w1 c">有货</p>
                            </c:if>
                            <c:if test="${name==null}">
                            <script type="text/javascript">
                            function ck(){
                                    alert("你未登入，请去登入吧！");
                                    return false;
                            }
                            </script>

                            </c:if>