1.后台管理—分页显示

1.程序框架图

2.编写数据模型

Page.java

package com.sxs.furns.entity;import java.util.List;/*** @author 孙显圣* @version 1.0*/
public class Page<T> {public static final Integer PAGE_SIZE = 3; //每页显示几条记录private Integer pageNo; //表示当前页private Integer pageSize = PAGE_SIZE; //表示每页显示几条记录private Integer pageTotalCount; //表示共有几页private Integer totalRow; //表示共有多少条记录private List<T> items; //表示当前页显示的数据private String url; //分页导航的字符串public Integer getPageNo() {return pageNo;}public void setPageNo(Integer pageNo) {this.pageNo = pageNo;}public Integer getPageSize() {return pageSize;}public void setPageSize(Integer pageSize) {this.pageSize = pageSize;}public Integer getPageTotalCount() {return pageTotalCount;}public void setPageTotalCount(Integer pageTotalCount) {this.pageTotalCount = pageTotalCount;}public Integer getTotalRow() {return totalRow;}public void setTotalRow(Integer totalRow) {this.totalRow = totalRow;}public List<T> getItems() {return items;}public void setItems(List<T> items) {this.items = items;}public String getUrl() {return url;}public void setUrl(String url) {this.url = url;}
}

3.编写dao层

1.修改FurnDao

增加方法

    //获取记录总数public int getTotalRow();//获取当前页要显示的数据public List<Furn> getPageItems(int begin, int pageSize);

2.修改FurnDaoImpl

增加方法

    /*** 获取总的记录条数** @return 返回总的记录条数*/@Overridepublic int getTotalRow() {String sql = "SELECT COUNT(*) FROM furn";//注意这里的类型转换return ((Number) queryScalar(sql)).intValue();}/*** 获取当页要显示的数据** @param begin 从第几条记录开始获取* @param pageSize 每页的大小* @return*/@Overridepublic List<Furn> getPageItems(int begin, int pageSize) {String sql ="select * from furn limit ?, ?";return queryMulti(sql, Furn.class, begin, pageSize);}

3.单元测试

FurnDaoTest

    @Testpublic void getTotalRow() {System.out.println("记录总数为：" + furnDao.getTotalRow());}@Testpublic void getPageItems() {List<Furn> pageItems = furnDao.getPageItems(3, 3);if (pageItems != null) {for (Furn pageItem : pageItems) {System.out.println(pageItem);}}}

4.编写service层

1.修改FurnService

增加方法

    //6.根据传入的begin和pageSize返回对应的page对象public Page<Furn> page(int pageNo, int pageSize);

2.修改FurnServiceImpl

增加方法

    /*** 根据传入的页号和每页的大小，返回page** @param pageNo* @param pageSize* @return 返回page*/@Overridepublic Page<Furn> page(int pageNo, int pageSize) {Page<Furn> page = new Page<>();page.setPageNo(pageNo);page.setPageSize(pageSize);int totalRow = furnDao.getTotalRow();page.setTotalRow(totalRow);//计算总页数int pageTotalCount = totalRow / pageSize;if (totalRow % pageSize > 0) {pageTotalCount += 1;}page.setPageTotalCount(pageTotalCount);//计算当前页显示的记录int begin = pageSize * (pageNo - 1);List<Furn> pageItems = furnDao.getPageItems(begin, pageSize);page.setItems(pageItems);return page;}

3.单元测试

FurnServiceTest

5.编写DataUtils

增加方法

    /*** 字符串转换为Integer** @param str 传入的字符串* @param def 默认值* @return*/public static Integer parseInt(String str, Integer def) {if (null == str || "".equals(str)) {return  def;} else {return Integer.parseInt(str);}}

6.编写FurnServlet

增加方法

    /*** 处理分页请求* @param req* @param resp*/public void page(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//获取pageNo和pageSizeInteger pageNo = DataUtils.parseInt(req.getParameter("pageNo"), 1);Integer pageSize = DataUtils.parseInt(req.getParameter("pageSize"), Page.PAGE_SIZE);//调用方法获取page对象Page<Furn> page = furnService.page(pageNo, pageSize);//将page放入request域请求转发到前端req.setAttribute("page", page);req.getRequestDispatcher("/views/manage/furn_manage.jsp").forward(req, resp);}

7.修改manage_menu.jsp

8.修改furn_manage.jsp

9.结果展示

1.点击家居管理

2.只展示当前页的三个数据

2.后台分页导航

1.需求分析

2.完成底部分页

1.修改furn_manage.jsp

        <!--  Pagination Area Start 分页导航条 --><div class="pro-pagination-style text-center mb-md-30px mb-lm-30px mt-6" data-aos="fade-up"><ul><li><a href="manage/furnServlet?action=page&pageNo=1">首页</a></li><%--有上一页再显示--%><c:if test="${requestScope.page.pageNo-1 > 0}"><li><a href="manage/furnServlet?action=page&pageNo=${requestScope.page.pageNo-1}">上页</a></li></c:if><%--最多显示5页--%><c:forEach begin="${requestScope.page.pageNo - 2 > 0 ? requestScope.page.pageNo - 2 : 1}" end="${requestScope.page.pageNo+2}" var="pageNo"><%--页数在范围内才显示--%><c:if test="${pageNo >= 1 && pageNo <= requestScope.page.pageTotalCount}"><li><%-- 如果是当前页号则显示被选中--%><a class="<c:if test="${requestScope.page.pageNo == pageNo}">active</c:if>"href="manage/furnServlet?action=page&pageNo=${pageNo}#">${pageNo}</a></li></c:if></c:forEach><%--有下一页再显示--%><c:if test="${requestScope.page.pageNo+1 <= requestScope.page.pageTotalCount}"><li><a href="manage/furnServlet?action=page&pageNo=${requestScope.page.pageNo+1}">下页</a></li></c:if><li><a href="manage/furnServlet?action=page&pageNo=${requestScope.page.pageTotalCount}">末页</a></li><li><a>共${requestScope.page.pageTotalCount}页</a></li><li><a>共${requestScope.page.totalRow}记录</a></li></ul></div><!--  Pagination Area End -->

2.结果展示

1.限制显示5页

2.末页只显示前面两页

3.首页只显示后面两页

3.完成修改家居后跳转原页面

1.修改furn_manage.jsp

2.修改furn_update.jsp

3.修改FurnServlet

更新updateFurn方法

    /*** 读取表单信息，进行修改** @param req* @param resp*/public void updateFurn(HttpServletRequest req, HttpServletResponse resp) throws IOException {//获取pageNoString pageNo = req.getParameter("pageNo");//使用工具类将表单信息封装到bean中Furn furn = DataUtils.copyParamToBean(req.getParameterMap(), new Furn());//执行更新操作if (furnService.updateFurn(furn)) {//更新成功则重定向到展示页面resp.sendRedirect(super.getServletContext().getContextPath() + "/manage/furnServlet?action=page&pageNo=" + pageNo);} else {System.out.println("更新失败");}}

4.结果展示

1.修改前是第4页

2.点击修改

3.回到第4页

4.完成删除家居后跳转原页面

1.修改furn_manage.jsp

2.修改FurnServlet

更新del方法

    /*** 根据获取的id删除家居，获取家居信息并重定向到furn_manage.jsp** @param req* @param resp*/public void del(HttpServletRequest req, HttpServletResponse resp) throws IOException {//获取idString id = req.getParameter("id");//获取pageNoString pageNo = req.getParameter("pageNo");//根据id删除if (furnService.deleteFurnById(Integer.parseInt(id))) {resp.sendRedirect(super.getServletContext().getContextPath() + "/manage/furnServlet?action=page&pageNo=" + pageNo);} else {System.out.println("删除失败");}}

3.结果展示

1.删除前是第四页

2.删除后还是第四页

5.完成添加家居后跳转原页面

1.修改furn_manage.jsp

2.修改furn_add.jsp

3.修改FurnServlet

更新add方法

    /*** 添加家居并重新获取家居信息，重定向到furn_manage.jsp** @param req* @param resp*/public void add(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException, InvocationTargetException, IllegalAccessException {//使用工具类封装并处理异常Furn furn = DataUtils.copyParamToBean(req.getParameterMap(), new Furn());//获取pageNoString pageNo = req.getParameter("pageNo");//插入到数据库if (furnService.add(furn)) {//插入成功则重定向到家居显示的servletresp.sendRedirect(super.getServletContext().getContextPath() + "/manage/furnServlet?action=page&pageNo=" + pageNo);} else {System.out.println("插入失败");}}

4.结果展示

1.添加家居前是第3页

2.添加家居后还是3页

3.首页分页

1.需求分析

2.分页显示家居

1.编写CustomerFurnServlet

CustomerFurnServlet.java

package com.sxs.furns.web;import com.sxs.furns.entity.Furn;
import com.sxs.furns.entity.Page;
import com.sxs.furns.service.FurnService;
import com.sxs.furns.service.impl.FurnServiceImpl;
import com.sxs.furns.utils.DataUtils;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;/*** @author 孙显圣* @version 1.0*/
@WebServlet(urlPatterns = "/customerFurnServlet")
public class CustomerFurnServlet extends BasicServlet{FurnService furnService = new FurnServiceImpl();/*** 根据pageNo和pageSize,将page对象请求转发到index.jsp*/public void page(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//获取pageNo和pageSizeInteger pageNo = DataUtils.parseInt(req.getParameter("pageNo"), 1);Integer pageSize = DataUtils.parseInt(req.getParameter("pageSize"), 8);//调用service层，获取page对象Page<Furn> page = furnService.page(pageNo, pageSize);//请求转发到index.jspreq.setAttribute("page", page);req.getRequestDispatcher("/views/customer/index.jsp").forward(req, resp);}
}

2.修改index.jsp

<%--Date: 2024/2/4Time: 18:42User: 孙显圣Version:1.0
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>$Title$</title>
</head>
<body>
<%-- 网站入口，请求转发到/customerFurnServlet--%><jsp:forward page="/customerFurnServlet?action=page"></jsp:forward>
</body>
</html>

3.index.html修改为index.jsp

1.修改头部

2.遍历显示家居

3.分页导航条设置

修改index.jsp

4.单元测试

图片重复问题

原因

1. 查询的时候直接查的所有数据，select *
2. 但是javabean中的字段和imgPath 和 表中的字段img_Path不符，所以无法封装进去，就使用了之前设置的默认值
3. 在查找的时候设置一个别名即可

5.结果展示

1.首页显示

2.分页导航条设置