案例24-商品浏览历史记录

时间 2019-11-24

标签案例商品浏览历史记录繁體版

原文原文链接

1 案例效果

2 案例分析

3 web层部分

1 ProductInfoServlet 代码修改

package www.test.web.servlet;

import java.io.IOException;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

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

import www.test.domain.Product;
import www.test.service.ProductService;

public class ProductInfoServlet extends HttpServlet {

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

        //获取cid和当前页
        String cid = request.getParameter("cid");
        String currentPage = request.getParameter("currentPage");
        
        //获取pid
        String pid =request.getParameter("pid");
        
        //传递给service层并调取service层的方法
        ProductService service = new ProductService();
        Product product = null;
        try {
            product = service.findProductByPid(pid);
        } catch (SQLException e) {
            
            e.printStackTrace();
        }
        
        
        //存储到request域中
        request.setAttribute("product", product);
        request.setAttribute("cid", cid);
        request.setAttribute("currentPage", currentPage);
        
        
        //获取客户端携带的cookie----得到名字是pids的cookie String pids = pid; Cookie[] cookies = request.getCookies(); if(cookies!=null){ for(Cookie cookie:cookies){ if("pids".equals(cookie.getName())){ pids = cookie.getValue(); //1-3-2 本次访问的商品的pid是8----->8-1-3-2 //1-3-2 本次访问的商品的pid是3----->3-1-2 //1-3-2 本次访问的商品的pid是1----->2-1-3 //将pids拆成一个数组 String[] split = pids.split("-");//{3,1,2} //数组转换成集合 List<String> asList = Arrays.asList(split);//[3,1,2] LinkedList<String> list = new LinkedList<String>(asList); //[3,1,2] //判断集合中是否存在当前的pid /*if(list.contains(pid)){ //包含当前查看的商品的pid //先删掉而后放在头上 list.remove(pid); list.addFirst(pid); }else{ //不包含当前查看的商品的pid 直接将该pid放在头上 list.addFirst(pid); }*/ //上面代码的优化 //无论包不包含都须要放到头上 if(list.contains(pid)){ //包含当前查看的商品的pid  list.remove(pid); } list.addFirst(pid); //将[3,1,2]转成3-1-2字符串 StringBuffer sb = new StringBuffer(); for(int i=0;i<list.size()&&i<7;++i){ //&&i<7 页面最多显示7个浏览商品的历史记录 sb.append(list.get(i)); sb.append("-"); //3-1-2-  } //去掉3-1-2-后面的- //substring包含头不包含尾 pids = sb.substring(0, sb.length()-1); } } } //建立cookie回写 Cookie cookie_pids = new Cookie("pids", pids); cookie_pids.setMaxAge(60*60); //单位为秒 设置cookie的存储事件一个小时 //设置cookie的携带路径  cookie_pids.setPath(request.getContextPath()); //将cookie_pids写回去  response.addCookie(cookie_pids); //转发
        request.getRequestDispatcher("/product_info.jsp").forward(request, response);
    }

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

}

2 ProductListByCidServlet 代码修改

package www.test.web.servlet;

import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

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

import www.test.domain.Product;
import www.test.service.ProductService;
import www.test.vo.PageBean;

public class ProductListByCidServlet extends HttpServlet {

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

        //获取cid
        String cid = request.getParameter("cid");
        String currentPageStr = request.getParameter("currentPage");
        if(currentPageStr == null){
            currentPageStr = "1";
        }
        int currentPage = Integer.parseInt(currentPageStr);
        int currentCount =12;
        //根据cid查询商品
        ProductService service = new ProductService();
        PageBean<Product> pageBean = service.findProductListByCid(cid,currentPage,currentCount);
        
        request.setAttribute("pageBean", pageBean);
        request.setAttribute("cid", cid);
        
        //定义一个集合记录历史商品信息的集合 List<Product> historyProductList = new ArrayList<Product>();
        
        
        //获取客户端携带的名字叫pids的cookie Cookie[] cookies = request.getCookies(); if(cookies!=null){ for (Cookie cookie : cookies) { if("pids".equals(cookie.getName())){ String pids = cookie.getValue(); //3-1-2 String[] split = pids.split("-"); for(String pid:split){ Product product =null; try { product = service.findProductByPid(pid); historyProductList.add(product); } catch (SQLException e) { e.printStackTrace(); } } } } } //将历史记录的集合放到域中 request.setAttribute("historyProductList", historyProductList); //转发
        request.getRequestDispatcher("/product_list.jsp").forward(request, response);
    }

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

4 WebContent部分

1 product_list.jsp代码修改

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>会员登陆</title>
<link rel="stylesheet" href="css/bootstrap.min.css" type="text/css" />
<script src="js/jquery-1.11.3.min.js" type="text/javascript"></script>
<script src="js/bootstrap.min.js" type="text/javascript"></script>
<!-- 引入自定义css文件 style.css -->
<link rel="stylesheet" href="css/style.css" type="text/css" />

<style>
body {
    margin-top: 20px;
    margin: 0 auto;
    width: 100%;
}

.carousel-inner .item img {
    width: 100%;
    height: 300px;
}
</style>
</head>

<body>


    <!-- 引入header.jsp -->
    <jsp:include page="/header.jsp"></jsp:include>


    <div class="row" style="width: 1210px; margin: 0 auto;">
        <div class="col-md-12">
            <ol class="breadcrumb">
                <li><a href="#">首页</a></li>
            </ol>
        </div>
        <c:forEach items="${pageBean.list }" var="product">
            <div class="col-md-2" style="height: 250px">
                <a href="${pageContext.request.contextPath }/productInfo?pid=${product.pid}&cid=${cid}&currentPage=${pageBean.currentPage}"> <img src="${pageContext.request.contextPath }/${product.pimage}"
                    width="170" height="170" style="display: inline-block;">
                </a>
                <p>
                    <a href="${pageContext.request.contextPath }/productInfo?pid=${product.pid}&cid=${cid}&currentPage=${pageBean.currentPage}" style='color: green'>${product.pname }</a>
                </p>
                <p>
                    <font color="#FF0000">商城价：&yen;${product.shop_price }</font>
                </p>
            </div>
        </c:forEach>
    </div>

    <!--分页 -->
    <div style="width: 380px; margin: 0 auto; margin-top: 50px;">
        <ul class="pagination" style="text-align: center; margin-top: 10px;">
            
                    
            
            <!-- 2 上一页 -->
                <!--判断当前页是不是第一页  -->
            <c:if test="${pageBean.currentPage==1 }">
                <li class="disabled">
                    <a href="javascript:void(0);" aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
            </c:if>
            <c:if test="${pageBean.currentPage!=1 }">
                <li>
                    <a href="${pageContext.request.contextPath }/productListByCid?cid=${cid}&currentPage=${pageBean.currentPage-1 }" aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
            </c:if>
            
            
            
            
            <!-- 1 显示每一页 -->        
            <c:forEach begin="1" end="${pageBean.totalPage }" var="page">
                <!-- 判断是不是当前页 -->
                <c:if test="${page==pageBean.currentPage }">
                    <li class="active"><a href="javascript:void(0);">${page }</a></li>
                </c:if> 
                <c:if test="${page!=pageBean.currentPage }">
                    <li><a href="${pageContext.request.contextPath }/productListByCid?cid=${cid}&currentPage=${page }">${page }</a></li>
                </c:if>
            </c:forEach>
            
            
            
            <!-- 3 下一页 -->
                <!--判断当前页是不是第一页  -->
            <c:if test="${pageBean.currentPage==pageBean.totalPage }">
                <li class="disabled">
                    <a href="javascript:void(0);" aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
            </c:if>
            <c:if test="${pageBean.currentPage!=pageBean.totalPage }">
                <li>
                    <a href="${pageContext.request.contextPath }/productListByCid?cid=${cid}&currentPage=${pageBean.currentPage+1 }" aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
            </c:if>

            
        </ul>
    </div>
    <!-- 分页结束 -->

    <!--商品浏览记录-->
    <div
        style="width: 1210px; margin: 0 auto; padding: 0 9px; border: 1px solid #ddd; border-top: 2px solid #999; height: 246px;">

        <h4 style="width: 50%; float: left; font: 14px/30px 微软雅黑">浏览记录</h4>
        <div style="width: 50%; float: right; text-align: right;">
            <a href="">more</a>
        </div>
        <div style="clear: both;"></div>

        <div style="overflow: hidden;">

            <ul style="list-style: none;">
                <c:forEach items="${historyProductList }" var="historyPro"> <li style="width: 150px; height: 216; float: left; margin: 0 8px 0 0; padding: 0 18px 15px; text-align: center;"> <img src="${pageContext.request.contextPath }/${historyPro.pimage}" width="130px" height="130px" /> </li> </c:forEach>
                
            </ul>

        </div>
    </div>


    <!-- 引入footer.jsp -->
    <jsp:include page="/footer.jsp"></jsp:include>

</body>

</html>