<%@ 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
