分页查询功能
分页查询功能-分析
分析：
分页查询功能-代码实现-分页具体步骤
分页查询功能-代码实现-后台代码实现
创建PageBean类
package com.jstl.domain; import java.util.List; /** * 分页对象 */ public class PageBean<T> { private int totalCount; // 总记录数 private int totlePage; // 总页码 private List<T> list; // 每页的数据 private int currenPage; // 当前页面 private int rows; //每页显示的记录数 @Override public String toString() { return "PageBean{" + "totalCount=" + totalCount + ", totlePage=" + totlePage + ", list=" + list + ", currenPage=" + currenPage + ", rows=" + rows + '}'; } public int getTotalCount() { return totalCount; } public void setTotalCount(int totalCount) { this.totalCount = totalCount; } public int getTotlePage() { return totlePage; } public void setTotlePage(int totlePage) { this.totlePage = totlePage; } public List<T> getList() { return list; } public void setList(List<T> list) { this.list = list; } public int getCurrenPage() { return currenPage; } public void setCurrenPage(int currenPage) { this.currenPage = currenPage; } public int getRows() { return rows; } public void setRows(int rows) { this.rows = rows; } }
UserDao创建两个方法
/** * 查询总记录数 * @return */ int findTotalCount(); /** * 分页查询每页记录 * @param start * @param rows * @return */ List<User> findByPage(int start,int rows);
UserDaoImpl重写方法
@Override public int findTotalCount() { // 1.定义模板初始化sql String sql = "select count(*) from user where 1 = 1"; return template.queryForObject(sql,Integer.class); } @Override public List<User> findByPage(int start, int rows) { String sql = "select * from user where 1 = 1"; return template.query(sql,new BeanPropertyRowMapper<User>(User.class),start,rows); }
UserService创建方法
PageBean<User> findUserByPage(String currentPage,String rows);
UserServiceImpl重写方法
@Override public PageBean<User> findUserByPage(String _currentPage, String _rows) { int currentPage = Integer.parseInt(_currentPage); int rows = Integer.parseInt(_rows); if (currentPage <= 0) { currentPage = 1; } // 1.创建空的PageBean对象 PageBean<User> pb = new PageBean<>(); // 2.设置参数 pb.setCurrenPage(currentPage); pb.setRows(rows); // 3.调用dao查询总记录数 int totalCount = dao.findTotalCount(); pb.setRows(totalCount); // 4.调用dao查询List集合 // 计算开始的记录索引 int start = (currentPage - 1) * rows; List<User> list = dao.findByPage(start, rows); pb.setList(list); // 5.计算总页码 int totalPage = (totalCount % rows) == 0 ? totalCount / rows : (totalCount / rows) + 1; pb.setTotlePage(totalPage); return pb; }
新建FindUserByPageServlet类
package com.jstl.web.servlet; import com.jstl.domain.PageBean; import com.jstl.domain.User; import com.jstl.service.impl.UserServiceImpl; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.io.IOException; @WebServlet("/findUserByPageServlet ") public class FindUserByPageServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 获取参数 String currentPage = request.getParameter("currentPage"); String rows = request.getParameter("rows"); // 调用service查询 UserServiceImpl userService = new UserServiceImpl(); PageBean<User> pd = userService.findUserByPage(currentPage, rows); System.out.println(pd); // 将PageBean存入request request.setAttribute("pd",pd); // 转发list.jsp request.getRequestDispatcher("/list.jsp").forward(request,response); } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }
分页查询功能-代码实现-前台代码实现
修改FindUserByPageServlet
package com.jstl.web.servlet; import com.jstl.domain.PageBean; import com.jstl.domain.User; import com.jstl.service.impl.UserServiceImpl; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.io.IOException; @WebServlet("/findUserByPageServlet ") public class FindUserByPageServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //获取参数 String currentPage = req.getParameter("currentPage"); String rows = req.getParameter("rows"); if(currentPage == null || "".equals(currentPage)){ currentPage = "1"; } if(rows == null || "".equals(rows)){ rows = "5"; } //调用service查询 UserServiceImpl userService = new UserServiceImpl(); PageBean<User> pd = userService.findUserByPage(currentPage,rows); System.out.println(pd); //将PageBean存入request req.setAttribute("pd",pd); //转发到list.jsp req.getRequestDispatcher("/list.jsp").forward(req,resp); } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }
修改list.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <!DOCTYPE html> <!-- 网页使用的语言 --> <html lang="zh-CN"> <head> <!-- 指定字符集 --> <meta charset="utf-8"> <!-- 使用Edge最新的浏览器的渲染方式 --> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。 width: 默认宽度与设备的宽度相同 initial-scale: 初始的缩放比，为1:1 --> <meta name="viewport" content="width=device-width, initial-scale=1"> <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ --> <title>用户信息管理系统</title> <!-- 1. 导入CSS的全局样式 --> <link href="css/bootstrap.min.css" rel="stylesheet"> <!-- 2. jQuery导入，建议使用1.9以上的版本 --> <script src="js/jquery-2.1.0.min.js"></script> <!-- 3. 导入bootstrap的js文件 --> <script src="js/bootstrap.min.js"></script> <style type="text/css"> td, th { text-align: center; } </style> <script> function deleteUser(id){ //用户安全提示 if(confirm("您确定要删除吗？")){ //访问路径 location.href="${pageContext.request.contextPath}/delUserServlet?id="+id; } } window.onload = function(){ //给删除选中按钮添加单击事件 document.getElementById("delSelected").onclick = function(){ if(confirm("您确定要删除选中条目吗？")){ var flag = false; //判断是否有选中条目 var cbs = document.getElementsByName("uid"); for (var i = 0; i < cbs.length; i++) { if(cbs[i].checked){ //有一个条目选中了 flag = true; break; } } if(flag){//有条目被选中 //表单提交 document.getElementById("form").submit(); } } } //1.获取第一个cb document.getElementById("firstCb").onclick = function(){ //2.获取下边列表中所有的cb var cbs = document.getElementsByName("uid"); //3.遍历 for (var i = 0; i < cbs.length; i++) { //4.设置这些cbs[i]的checked状态 = firstCb.checked cbs[i].checked = this.checked; } } } </script> </head> <body> <div class="container"> <h3 style="text-align: center">用户信息列表</h3> <div style="float: left;"> <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post"> <div class="form-group"> <label for="exampleInputName2">姓名</label> <input type="text" name="name" value="${condition.name[0]}" class="form-control" id="exampleInputName2" > </div> <div class="form-group"> <label for="exampleInputName3">籍贯</label> <input type="text" name="address" value="${condition.address[0]}" class="form-control" id="exampleInputName3" > </div> <div class="form-group"> <label for="exampleInputEmail2">邮箱</label> <input type="text" name="email" value="${condition.email[0]}" class="form-control" id="exampleInputEmail2" > </div> <button type="submit" class="btn btn-default">查询</button> </form> </div> <div style="float: right;margin: 5px;"> <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp">添加联系人</a> <a class="btn btn-primary" href="javascript:void(0);" id="delSelected">删除选中</a> </div> <form id="form" action="${pageContext.request.contextPath}/delSelectedServlet" method="post"> <table border="1" class="table table-bordered table-hover"> <tr class="success"> <th><input type="checkbox" id="firstCb"></th> <th>编号</th> <th>姓名</th> <th>性别</th> <th>年龄</th> <th>籍贯</th> <th>QQ</th> <th>邮箱</th> <th>操作</th> </tr> <c:forEach items="${pb.list}" var="user" varStatus="s"> <tr> <td><input type="checkbox" name="uid" value="${user.id}"></td> <td>${s.count}</td> <td>${user.name}</td> <td>${user.gender}</td> <td>${user.age}</td> <td>${user.address}</td> <td>${user.qq}</td> <td>${user.email}</td> <td><a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}">修改</a> <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});">删除</a></td> </tr> </c:forEach> </table> </form> <div> <nav aria-label="Page navigation"> <ul class="pagination"> <c:if test="${pb.currentPage == 1}"> <li class="disabled"> </c:if> <c:if test="${pb.currentPage != 1}"> <li> </c:if> <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage - 1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous"> <span aria-hidden="true">«</span> </a> </li> <c:forEach begin="1" end="${pb.totalPage}" var="i" > <c:if test="${pb.currentPage == i}"> <li class="active "><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li> </c:if> <c:if test="${pb.currentPage != i}"> <li><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li> </c:if> </c:forEach> <li> <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage + 1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Next"> <span aria-hidden="true">»</span> </a> </li> <span style="font-size: 25px;margin-left: 5px;"> 共${pb.totalCount}条记录，共${pb.totalPage}页 </span> </ul> </nav> </div> </div> </body> </html>
