JSP新闻系统之七分页实现简化版

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package com.news.util;/** * 有了记录总条数后，页面控制类； * 根据总记录数，每页显示条数，来得到总页数; * @author Administrator * */public class PageControler {public int getTotalPages(int count,int pageSize){int totalPages=0;//如果总记录数除以每页显示条数，能够整除;//总页数就是它们的商，否则为商+1if(count%pageSize==0){totalPages=count/pageSize;}else{totalPages=count/pageSize+1;}return totalPages;}}

UserDao中的抽象方法//通过查询获取数据表中数据总条数;public int getCount();//根据当前页码和页数，来分页的方法;返回User集合;public List<User>queryUserByPage(int currentPage,int pageSize);//UserDaoImpl实现类中的方法/* 获得user的总个数,即要分页的总记录数 * @see com.news.dao.UserDao#getCount() */@Overridepublic int getCount() {Connection con=null;Statement st=null;ResultSet rs=null;int count=0;try {con=DaoFactory.getConnection();st=con.createStatement();String sql="select count(*) from t_user";rs=st.executeQuery(sql);if(rs.next()){count=rs.getInt(1);}} catch (SQLException e) {e.printStackTrace();}finally{DaoFactory.closeAll(rs, st, con);}return count;}@Overridepublic List<User> queryUserByPage(int currentPage, int pageSize) {Connection con=null;Statement st=null;ResultSet rs=null;List<User>users=null;try {con=DaoFactory.getConnection();st=con.createStatement();users=new ArrayList<User>();String sql="select top "+pageSize+" * from t_user where id not in (select top "+(currentPage-1)*pageSize+" id from t_user order by id)order by id";rs=st.executeQuery(sql);//遍历结果集while(rs.next()){//从数据库中取出一条记录后，放到实体对象中;User user=new User();user.setId(rs.getInt("id"));user.setUsername(rs.getString("username"));user.setEmail(rs.getString("email"));user.setAddress(rs.getString("address"));user.setHobby(rs.getString("hobby"));//将实体对象放入集合中;users.add(user);}} catch (SQLException e) {e.printStackTrace();}finally{DaoFactory.closeAll(rs, st, con);}return users;}

show_user.jsp页面代码如下

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><%@ page import="com.news.dao.*,com.news.dao.impl.*,com.news.entity.*,com.news.util.*" %><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><link rel="stylesheet" type="text/css" href="css/css.css">  </head>    <body>  <table border="1" align="center">  <caption>=用户列表</caption>  <tr>  <td>编号</td>  <td>账号</td>  <td>密码</td>  <td>邮箱</td>  <td>住址</td>  <td>爱好</td>  </tr>  <%   //获取当前页码，如果获取不到，默认是第一页;   String pageIndex=request.getParameter("pageIndex");   if(pageIndex==null){   pageIndex="1";   }   int currentPage=Integer.parseInt(pageIndex);   int pageSize=4;   UserDao ud=new UserDaoImpl();   PageControler pc=new PageControler();   int count=ud.getCount();   //获得总页数;   int totalPages=pc.getTotalPages(count,pageSize);   //分页查询，得到当前页数数据;   List<User>users=ud.queryUserByPage(currentPage,pageSize);   for(int i=0;i<users.size();i++){   User user=users.get(i);    %>  <tr>  <td><%=user.getId() %></td>  <td><%=user.getUsername() %></td>  <td><%=user.getPwd() %></td>  <td><%=user.getEmail() %></td>  <td><%=user.getAddress() %></td>  <td><%=user.getHobby() %></td>  </tr>  <%  }   %>   <!-- 分页控制 -->   <tr class="altrow">   <td colspan="6">   第<%=currentPage %>页/共<%=totalPages %>页   <a href='admin/show_user.jsp?pageIndex=<%=1 %>'>首页</a>   <%    if(currentPage>1){    %>    <a href='admin/show_user.jsp?pageIndex=<%=currentPage-1 %>'>上一页||</a>    <%    }    if(currentPage<totalPages){     %>     <a href='admin/show_user.jsp?pageIndex=<%=currentPage+1 %>'>下一页</a>||     <%} %>     <a href='admin/show_user.jsp?pageIndex=<%=totalPages %>'>末页</a>   </td>   </tr>  </table>     </body></html>

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JSP新闻系统之七 分页实现简化版

JSP新闻系统之七分页实现简化版