java--分页技术
Posted xanlv
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<html>
<body>
<c:redirect url="/page"></c:redirect>
</body>
</html>
show.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<html>
<head>
<script type="text/javascript">
function sub(obj)
window.location.href="<c:url value='/page?pageNo="+obj.value+"'/>";
</script>
</head>
<body>
<h3>学生信息</h3>
<c:forEach items="$result.students" var="s">
id=$s.id,,,name=$s.name<br/>
</c:forEach>
pageCount=$result.pageCount<br/>
<select onchange="sub(this)">
<c:forEach begin="1" end="$result.pageCount" var="idx">
<%--
<option selected='<c:if test="$idx==result.currentPage">selected</c:if>' value="$idx">第$idx页</option>
--%>
<option <c:if test="$idx==result.currentPage">selected</c:if> value="$idx">第$idx页</option>
</c:forEach>
</select>
<br/><br/>
<c:if test="$result.currentPage>1">
<a href='<c:url value="/page?pageNo=$result.currentPage-1"></c:url>'>上一页</a>
</c:if>
<c:forEach begin="1" end="$result.pageCount" var="idx">
<c:if test="$result.currentPage==idx">
$idx
</c:if>
<c:if test="$result.currentPage!=idx">
<a href='<c:url value="/page?pageNo=$idx"></c:url>'>$idx</a>
</c:if>
</c:forEach>
<c:if test="$result.currentPage<result.pageCount">
<a href='<c:url value="/page?pageNo=$result.currentPage+1"></c:url>'>下一页</a>
</c:if>
<br/><br/>
</body>
</html>
C3p0Utils.java见http://blog.csdn.net/xanlv/article/details/53266493
值对象Stud.java
package cn.hncu.domain;
public class Stud
private String id;
private String name;
public String getId()
return id;
public void setId(String id)
this.id = id;
public String getName()
return name;
public void setName(String name)
this.name = name;
@Override
public String toString()
return "stud =" + id + "," + name;
servlet层
PageServlet.java
package cn.hncu.servlet;
import java.io.IOException;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.hncu.service.IPageService;
import cn.hncu.service.PageServiceImpl;
public class PageServlet extends HttpServlet
//依赖注入service
IPageService service=new PageServiceImpl();
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
doPost(request, response);
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
String pageNo=request.getParameter("pageNo");
if(pageNo==null||pageNo.equals(""))
pageNo="1";//默认查询第1页
try
//把页码转成int
int iPageNo=Integer.parseInt(pageNo);
Map<String, Object> result=service.query(iPageNo);
// System.out.println("--"+result.get("pageCount"));
// System.out.println("--"+result.get("students"));
//再补一个结果3: 当前页码
result.put("currentPage", iPageNo);
//结果数据一定要放在容器中
request.setAttribute("result", result);
//转发到结果页面去显示
request.getRequestDispatcher("/jsps/show.jsp").forward(request, response);
catch (NumberFormatException e)
response.getWriter().println("页码格式错误!");
catch (Exception e)
response.getWriter().println("数据库查询错误!");
service层
package cn.hncu.service;
import java.util.Map;
public interface IPageService
public Map<String, Object> query(Integer iPageNo) throws Exception ;
package cn.hncu.service;
import java.util.Map;
import cn.hncu.dao.PageDAO;
import cn.hncu.dao.PageDaoJdbc;
public class PageServiceImpl implements IPageService
//依赖注入dao
PageDAO dao=new PageDaoJdbc();
@Override
public Map<String, Object> query(Integer iPageNo) throws Exception
return dao.query(iPageNo);
dao层
package cn.hncu.dao;
import java.util.Map;
public interface PageDAO
public Map<String, Object> query(Integer iPageNo) throws Exception ;
package cn.hncu.dao;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import cn.hncu.pubs.C3p0Utils;
public class PageDaoJdbc implements PageDAO
@Override
public Map<String, Object> query(Integer iPageNo) throws Exception
int pageSize=20;//每页显示10行,本例这里写死了
Map<String, Object> result=new HashMap<String,Object>();
//查询总行数
String sql_1="select count(1) from student";
QueryRunner run=new QueryRunner(C3p0Utils.getDataSource());
Object obj=run.query(sql_1, new ScalarHandler());//使用ScalarHandler封装返回结果是1行1列的数据
// System.out.println("pageCount:"+obj.toString());
int rows=Integer.parseInt(obj.toString());
//计算出总页数
// int pageCount=rows/iPageNo+rows%iPageNo==0?0:1;
int pageCount=rows/pageSize+(rows%pageSize==0?0:1);
result.put("pageCount", pageCount);//结果1
System.out.println("row:"+rows);
System.out.println("pageCount:"+pageCount);
//查询当前页要显示的内容(数据行)
int startN = (iPageNo-1)*pageSize;//从哪一行开始显示
String sql_2="select * from student limit "+startN+","+pageSize;
// List<Map<String, String>> students=run.query(sql_2, new MapListHandler());//error
List<Map<String, Object>> students=run.query(sql_2, new MapListHandler());
// System.out.println(students);
result.put("students", students);//结果2
// System.out.println("ll"+result.get("students"));
return result;
访问项目的初始页面
显示第10页
最后一页
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