IGeekShop案例6-商品的分页显示

迷南。 2024-04-17 14:08 171阅读 0赞

IGeekShop案例6-商品的分页显示

1 预期效果

在这里插入图片描述

2 pageBean类

  1. package www.test.vo;
  3. import java.util.ArrayList;
  4. import java.util.List;
  6. public class PageBean<T> {
  8.     // 1 当前页
  9.     private int currentPage;
  10.     // 2 当前页显示的条数
  11.     private int currentCount;
  12.     // 3 总条数
  13.     private int totalCount;
  14.     // 4 总页数
  15.     private int totalPage;
  16.     // 5 每页显示的数据
  17.     private List<T> productList = new ArrayList<T>();
  19.     public int getCurrentPage() {
  20.         return currentPage;
  21.     }
  23.     public void setCurrentPage(int currentPage) {
  24.         this.currentPage = currentPage;
  25.     }
  27.     public int getCurrentCount() {
  28.         return currentCount;
  29.     }
  31.     public void setCurrentCount(int currentCount) {
  32.         this.currentCount = currentCount;
  33.     }
  35.     public int getTotalCount() {
  36.         return totalCount;
  37.     }
  39.     public void setTotalCount(int totalCount) {
  40.         this.totalCount = totalCount;
  41.     }
  43.     public int getTotalPage() {
  44.         return totalPage;
  45.     }
  47.     public void setTotalPage(int totalPage) {
  48.         this.totalPage = totalPage;
  49.     }
  51.     public List<T> getProductList() {
  52.         return productList;
  53.     }
  55.     public void setProductList(List<T> productList) {
  56.         this.productList = productList;
  57.     }
  58. }

3 web层

  1. package www.test.web;
  3. import java.io.IOException;
  4. import java.sql.SQLException;
  5. import java.util.List;
  7. import javax.servlet.ServletException;
  8. import javax.servlet.http.HttpServlet;
  9. import javax.servlet.http.HttpServletRequest;
  10. import javax.servlet.http.HttpServletResponse;
  12. import www.test.domain.Product;
  13. import www.test.service.ProductService;
  14. import www.test.vo.PageBean;
  16. public class ProductListServlet extends HttpServlet {
  18.     protected void doGet(HttpServletRequest request, HttpServletResponse response)
  19.             throws ServletException, IOException {
  21.         ProductService service = new ProductService();
  23.         //模拟当前是第一页
  24.         String currentPageStr = request.getParameter("currentPage");
  25.           //如果是直接访问productList的话，让currentPageStr=1；
  26.         if(currentPageStr==null) currentPageStr="1";
  27.         int currentPage = Integer.parseInt(currentPageStr);
  28.         //认为每页显示12条
  29.         int currentCount = 12;
  31.         PageBean<Product> pageBean = null;
  32.         try {
  33.             pageBean = service.findPageBean(currentPage,currentCount);
  34.         } catch (SQLException e) {
  35.             e.printStackTrace();
  36.         }
  38.         request.setAttribute("pageBean", pageBean);
  40.         request.getRequestDispatcher("/product_list.jsp").forward(request, response);
  42.     }
  44.     protected void doPost(HttpServletRequest request, HttpServletResponse response)
  45.             throws ServletException, IOException {
  46.         doGet(request, response);
  47.     }
  48. }

4 service层

  1. package www.test.service;
  3. import java.sql.SQLException;
  4. import java.util.ArrayList;
  5. import java.util.List;
  7. import www.test.dao.ProductDao;
  8. import www.test.domain.Product;
  9. import www.test.vo.PageBean;
  11. public class ProductService {
  13.     public List<Product> findAllProduct() throws SQLException {
  14.         ProductDao dao = new ProductDao();
  15.         return dao.findAllProduct();
  16.     }
  17.     //分页操作
  18.     public PageBean findPageBean(int currentPage,int currentCount) throws SQLException  {
  20.         ProductDao dao = new ProductDao();
  22.         //目的：就是想办法封装一个PageBean 并返回
  23.         PageBean pageBean = new PageBean();
  24.         //1、当前页private int currentPage;
  25.         pageBean.setCurrentPage(currentPage);
  26.         //2、当前页显示的条数private int currentCount;
  27.         pageBean.setCurrentCount(currentCount);
  28.         //3、总条数private int totalCount;
  29.         int totalCount = dao.getTotalCount();
  30.         pageBean.setTotalCount(totalCount);
  31.         //4、总页数private int totalPage;
  32.         /*
  33.          * 总条数        当前页显示的条数    总页数
  34.          * 10        4                3
  35.          * 11        4                3
  36.          * 12        4                3
  37.          * 13        4                4
  38.          * 
  39.          * 公式：总页数=Math.ceil(总条数/当前显示的条数)
  40.          * 
  41.          */
  42.         int totalPage = (int) Math.ceil(1.0*totalCount/currentCount);
  43.         pageBean.setTotalPage(totalPage);
  44.         //5、每页显示的数据private List<T> productList = new ArrayList<T>();
  45.         /*
  46.          * 页数与limit起始索引的关系
  47.          * 例如 每页显示4条
  48.          * 页数        其实索引        每页显示条数
  49.          * 1        0            4
  50.          * 2        4            4
  51.          * 3        8            4
  52.          * 4        12            4
  53.          * 
  54.          * 索引index = (当前页数-1)*每页显示的条数
  55.          * 
  56.          */
  57.         int index = (currentPage-1)*currentCount;
  59.         List<Product> productList = dao.findProductListForPageBean(index,currentCount);
  60.         pageBean.setProductList(productList);
  62.         return pageBean;
  63.     }
  65. }

5 dao层

  1. package www.test.dao;
  3. import java.sql.SQLException;
  4. import java.util.List;
  6. import org.apache.commons.dbutils.QueryRunner;
  7. import org.apache.commons.dbutils.handlers.BeanListHandler;
  8. import org.apache.commons.dbutils.handlers.ScalarHandler;
  10. import www.test.domain.Product;
  11. import www.test.utils.DataSourceUtils;
  13. public class ProductDao {
  15.     public List<Product> findAllProduct() throws SQLException {
  16.         return new QueryRunner(DataSourceUtils.getDataSource()).query("select * from product", new BeanListHandler<Product>(Product.class));
  17.     }
  19.     //获得全部的商品条数
  20.     public int getTotalCount() throws SQLException {
  21.         QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
  22.         String sql = "select count(*) from product";
  23.         Long query = (Long) runner.query(sql, new ScalarHandler());
  24.         return query.intValue();
  25.     }
  27.     //获得分页的商品数据
  28.     public List<Product> findProductListForPageBean(int index,int currentCount) throws SQLException {
  29.         QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
  30.         String sql = "select * from product limit ?,?";
  31.         return runner.query(sql, new BeanListHandler<Product>(Product.class), index,currentCount);
  32.     }
  34. }

6 product_list.jsp

  1. <%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
  2. <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
  3. <!DOCTYPE html>
  4. <html>
  5. <head>
  6. <meta name="viewport" content="width=device-width, initial-scale=1">
  7. <title>会员登录</title>
  8. <link rel="stylesheet" href="css/bootstrap.min.css" type="text/css" />
  9. <script src="js/jquery-1.11.3.min.js" type="text/javascript"></script>
  10. <script src="js/bootstrap.min.js" type="text/javascript"></script>
  11. <!-- 引入自定义css文件 style.css -->
  12. <link rel="stylesheet" href="css/style.css" type="text/css" />
  14. <style>
  15. body {
  16.     margin-top: 20px;
  17.     margin: 0 auto;
  18.     width: 100%;
  19. }
  21. .carousel-inner .item img {
  22.     width: 100%;
  23.     height: 300px;
  24. }
  25. </style>
  26. </head>
  28. <body>
  31.     <!-- 引入header.jsp -->
  32.     <jsp:include page="/header.jsp"></jsp:include>
  35.     <div class="row" style="width: 1210px; margin: 0 auto;">
  36.         <div class="col-md-12">
  37.             <ol class="breadcrumb">
  38.                 <li><a href="#">首页</a></li>
  39.             </ol>
  40.         </div>
  42.         <c:forEach items="${pageBean.productList }" var="product">
  43.             <div class="col-md-2" style="height:250px">
  44.                 <a href="product_info.htm"> 
  45.                     <img src="${pageContext.request.contextPath }/${product.pimage}" width="170" height="170" style="display: inline-block;">
  46.                 </a>
  47.                 <p>
  48.                     <a href="product_info.html" style='color: green'>${product.pname }</a>
  49.                 </p>
  50.                 <p>
  51.                     <font color="#FF0000">商城价：¥${product.shop_price }</font>
  52.                 </p>
  53.             </div>
  54.         </c:forEach>
  60.     </div>
  62.     <!--分页 -->
  63.     <div style="width: 380px; margin: 0 auto; margin-top: 50px;">
  64.         <ul class="pagination" style="text-align: center; margin-top: 10px;">
  65.             <!-- 上一页 -->
  66.             <!-- 判断当前页是否是第一页 -->
  67.             <c:if test="${pageBean.currentPage==1 }">
  68.                 <li class="disabled">
  69.                     <a href="javascript:void(0);" aria-label="Previous">
  70.                         <span aria-hidden="true">«</span>
  71.                     </a>
  72.                 </li>
  73.             </c:if>
  74.             <c:if test="${pageBean.currentPage!=1 }">
  75.                 <li>
  76.                     <a href="${pageContext.request.contextPath }/productList?currentPage=${pageBean.currentPage-1}" aria-label="Previous">
  77.                         <span aria-hidden="true">«</span>
  78.                     </a>
  79.                 </li>
  80.             </c:if>    
  85.             <c:forEach begin="1" end="${pageBean.totalPage }" var="page">
  86.                 <!-- 判断当前页 -->
  87.                 <c:if test="${pageBean.currentPage==page }">
  88.                     <li class="active"><a href="javascript:void(0);">${page}</a></li>
  89.                 </c:if>
  90.                 <c:if test="${pageBean.currentPage!=page }">
  91.                     <li><a href="${pageContext.request.contextPath }/productList?currentPage=${page}">${page}</a></li>
  92.                 </c:if>
  94.             </c:forEach>
  96.             <!-- 判断当前页是否是最后一页 -->
  97.             <c:if test="${pageBean.currentPage==pageBean.totalPage }">
  98.                 <li class="disabled">
  99.                     <a href="javascript:void(0);" aria-label="Next"> 
  100.                         <span aria-hidden="true">»</span>
  101.                     </a>
  102.                 </li>
  103.             </c:if>
  104.             <c:if test="${pageBean.currentPage!=pageBean.totalPage }">
  105.                 <li>
  106.                     <a href="${pageContext.request.contextPath }/productList?currentPage=${pageBean.currentPage+1}" aria-label="Next"> 
  107.                         <span aria-hidden="true">»</span>
  108.                     </a>
  109.                 </li>
  110.             </c:if>
  112.         </ul>
  113.     </div>
  114.     <!-- 分页结束 -->
  116.     <!--商品浏览记录-->
  117.     <div
  118.         style="width: 1210px; margin: 0 auto; padding: 0 9px; border: 1px solid #ddd; border-top: 2px solid #999; height: 246px;">
  120.         <h4 style="width: 50%; float: left; font: 14px/30px 微软雅黑">浏览记录</h4>
  121.         <div style="width: 50%; float: right; text-align: right;">
  122.             <a href="">more</a>
  123.         </div>
  124.         <div style="clear: both;"></div>
  126.         <div style="overflow: hidden;">
  128.             <ul style="list-style: none;">
  129.                 <li
  130.                     style="width: 150px; height: 216; float: left; margin: 0 8px 0 0; padding: 0 18px 15px; text-align: center;"><img
  131.                     src="products/1/cs10001.jpg" width="130px" height="130px" /></li>
  132.             </ul>
  134.         </div>
  135.     </div>
  138.     <!-- 引入footer.jsp -->
  139.     <jsp:include page="/footer.jsp"></jsp:include>
  141. </body>
  143. </html>

7 注意事项

1 取消超链 javascript:void(0);

2 分页查询

在这里插入图片描述

3 记住pageBean类

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