如何在jsp+servlet+javabean中实现数据分页？
本文实例讲述了jsp+servlet+javabean实现数据分页方法。分享给大家供大家参考，具体如下：
这里秉着且行且记的心态，记录下学习过程，学得快忘得快，生怕遗忘，以备日后使用。
用到的部分代码是自己在网上查找，并自己修改，加上自己的理解。也不知道算不算原创，只做自己学习记录。
使用相关：PostgreSQL数据库、dom4j、JSP、Servlet
一、首先是工程格局，来个全局视图方便读者与自己查看与使用
思路为：
以config.xml文件记录配置信息，以方便数据库更改，方便移植与重用。
DOM4JUtil.java用于解析xml属性文件以获得需要数据
PostgreSQL_Util.java分装数据连接与数据库操作
PageProperties.java为表格分页属性javaBean
PageProperties.java封装分页操作
Page.java为分页主要操作
tablePage.jsp为效果显示界面
用到的第三方jar包：
dom4j-1.6.1.jar用于xml文件解析
postgresql-9.3-1101.jdbc4.jar用于JDBC连接postgreSQL数据库
分页效果如下：能通过点击上页下页实现翻页，输入指定页面跳转(超出范围跳转到第1或最后页)。具体实现请参见详细代码，我都贴上来了。小菜鸟一名，处于正在学习阶段，有大神能指点下当然更好，希望不吝赐教！
二、具体代码实现
1、config.xml数据库连接信息属性文件
<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE postgres[ <!ELEMENT postgres (driver,url,username,pwd)> <!ELEMENT driver (#PCDATA)> <!ELEMENT url (#PCDATA)> <!ELEMENT username (#PCDATA)> <!ELEMENT pwd (#PCDATA)> ]> <postgres> <driver>org.postgresql.Driver</driver> <url>jdbc:postgresql://localhost:5432/java</url> <username>admin</username> <pwd>k42jc</pwd> </postgres>
2、DOM4JUtil.java
package util;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
/**
* 用于解析xml属性文件
* @author JohsonMuler
*
*/
public class DOM4JUtil {
private static Element root=null;
static{//静态代码块
//创建解析对象
SAXReader sr=new SAXReader();
//获取当前工程路径
// String url=System.getProperty("user.dir");
String url=DOM4JUtil.class.getResource("").getPath();
// System.out.println(url);
try {
//通过文件路径获取配置文件信息
Document doc=sr.read(url+"config.xml");
//获取根节点
root=doc.getRootElement();
} catch (DocumentException e) {
e.printStackTrace();
}
}
public static String getPostgresData(String str){
//以根节点为基础，获取配置文件数据
Element e=root.element(str);
String data=e.getText();
return data;
}
public static void main(String[] args) {
// String url=DOM4JUtil.class.getResource("..").getPath();
// System.out.println(System.getProperty("user.dir"));
// System.out.println(url);
String driver=getPostgresData("driver");
String url=getPostgresData("url");
System.out.println(driver);
System.out.println(url);
}
}
3、PostgreSQL_Util.java
package util;
import java.sql.PreparedStatement;
import java.sql.Statement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
public class PostgreSQL_Util {
private static DOM4JUtil dom=new DOM4JUtil();
private static Connection c=null;
private static ResultSet rs=null;
private static String driver=dom.getPostgresData("driver");
private static String url=dom.getPostgresData("url");
private static String username=dom.getPostgresData("username");
private static String pwd=dom.getPostgresData("pwd");
public PostgreSQL_Util(){
try {
Class.forName(driver);
c=DriverManager.getConnection(url);
} catch (ClassNotFoundException e) {
System.out.println("未找到指定类："+e.getMessage());
} catch (SQLException e) {
System.out.println("获取连接异常："+e.getMessage());
}
}
/**
* 数据查询方法(Statement)
* @param sql
* @return
* @throws SQLException
*/
public ResultSet executeQuery(String sql) throws SQLException{
Statement s=c.createStatement();
rs=s.executeQuery(sql);
return rs;
}
/**
* 重载方法(PreparedStatement)
* @param sql
* @param list
* @return
* @throws SQLException
*/
public ResultSet executeQuery(String sql,List<Object> list) throws SQLException{
PreparedStatement ps=c.prepareStatement(sql);
for(int i=0;i<list.size();i++){
System.out.println(list.get(i));
System.out.println(i+1);
ps.setObject(i+1, list.get(i));
}
rs=ps.executeQuery();
c.close();
return rs;
}
/**
* 数据更新方法(添加，删除，更改)(Statement)
* @param sql
* @throws SQLException
*/
public int executeUpdate(String sql) throws SQLException{
Statement s=c.createStatement();
int i=s.executeUpdate(sql);
c.close();
return i;
}
/**
* 重载方法(PreparedStatement)
* @param sql
* @param list
* @throws SQLException
*/
public int executeUpdate(String sql,List<Object> list) throws SQLException{
PreparedStatement ps=c.prepareStatement(sql);
for(int i=0;i<list.size();i++){
ps.setObject(i+1, list.get(i));
}
int i=ps.executeUpdate();
c.close();
return i;
}
/**
* 单独的获取连接
* @return
* @throws ClassNotFoundException
* @throws SQLException
*/
public static Connection getConnection() throws ClassNotFoundException, SQLException{
Class.forName(driver);
c=DriverManager.getConnection(url);
return c;
}
}
4、PageProperties.java
package bean;
import java.sql.ResultSet;
public class PageProperties {
private int currentPage;//当前页号
private int totalPages;//总页数
private int totalRecords;//总数据条数
private ResultSet rs;//动态结果集
public PageProperties() {
super();
}
public PageProperties(int currentPage, int totalPages, int totalRecords,
ResultSet rs) {
super();
this.currentPage = currentPage;
this.totalPages = totalPages;
this.totalRecords = totalRecords;
this.rs = rs;
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getTotalPages() {
return totalPages;
}
public void setTotalPages(int totalPages) {
this.totalPages = totalPages;
}
public int getTotalRecords() {
return totalRecords;
}
public void setTotalRecords(int totalRecords) {
this.totalRecords = totalRecords;
}
public ResultSet getRs() {
return rs;
}
public void setRs(ResultSet rs) {
this.rs = rs;
}
}
5、TablePage.java
package bean;
import java.sql.ResultSet;
public class PageProperties {
private int currentPage;//当前页号
private int totalPages;//总页数
private int totalRecords;//总数据条数
private ResultSet rs;//动态结果集
public PageProperties() {
super();
}
public PageProperties(int currentPage, int totalPages, int totalRecords,
ResultSet rs) {
super();
this.currentPage = currentPage;
this.totalPages = totalPages;
this.totalRecords = totalRecords;
this.rs = rs;
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getTotalPages() {
return totalPages;
}
public void setTotalPages(int totalPages) {
this.totalPages = totalPages;
}
public int getTotalRecords() {
return totalRecords;
}
public void setTotalRecords(int totalRecords) {
this.totalRecords = totalRecords;
}
public ResultSet getRs() {
return rs;
}
public void setRs(ResultSet rs) {
this.rs = rs;
}
}
6、Page.java这是主要处理类，Servlet
package servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import util.PostgreSQL_Util;
import bean.PageProperties;
import bean.TablePage;
public class Page extends HttpServlet {
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
/**
* 通过TablePage设置分页属性
*
*/
TablePage tb=new TablePage();
//获取当前表格显示的页码
int currentPage=tb.currentPage(tb.getStrPage(request, "page"));
System.out.println(currentPage);
//设置每页显示数据条数
tb.setPageRecord(10);//设置每页显示10条数据
/**
* 通过xxSQL_Util设置JDBC连接及数据处理
*/
PostgreSQL_Util postgres=new PostgreSQL_Util();
try {
ResultSet rs_count=postgres.executeQuery("select count(*) as c from student");
rs_count.next();
//获得总的数据条数
int totalRecords=rs_count.getInt("c");
//根据数据表的总数据条数获取页面显示表格的总页数
int totalPages=tb.getTotalPages(totalRecords);
if(currentPage>totalPages){
currentPage=totalPages;//保证最后一页不超出范围
}
//根据数据库表信息和当前页面信息获得动态结果集
ResultSet rs=tb.getPageResultSet(postgres.executeQuery("select * from student"), currentPage);
/**
* 将数据加入javaBean
*/
PageProperties pp=new PageProperties(currentPage, totalPages, totalRecords, rs);
/**
* 将javaBean转发至前端
*/
request.setAttribute("result", pp);
request.getRequestDispatcher("tablePage.jsp").forward(request, response);
} catch (SQLException e) {
System.out.println("Class Page:"+e.getMessage());
// e.printStackTrace();
}
}
}
7、tablePage.jsp前台显示效果
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="bean.PageProperties"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
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>
<title>简单数据分页</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="styles.css">
-->
</head>
<body>
<table>
<tr>
<td>姓名</td>
<td>性别</td>
<td>年龄</td>
<td>分数</td>
</tr>
<%
PageProperties pp=(PageProperties)request.getAttribute("result");
ResultSet rs=pp.getRs();
%>
<%
int i=1;
while(rs.next()){
%>
<tr>
<td><%=rs.getObject(1) %></td>
<td><%=rs.getObject(2) %></td>
<td><%=rs.getObject(3) %></td>
<td><%=rs.getObject(4) %></td>
</tr>
<%
i++;
if(i>10)
break;
}
%>
<br/>
<span><%=pp.getTotalPages() %>页</span>
<span>共<%=pp.getTotalRecords() %>条数据</span>
<span>本页<%=i-1 %>条</span>
<span>第<%=pp.getCurrentPage() %>页</span>
<p align="center">
<%
if ( pp.getCurrentPage() > 1 )
{
%><a href="<%=path %>/page?page=<%=pp.getCurrentPage() - 1%>"><<上一页</a>
<%
}
%>
<%
if ( pp.getCurrentPage() < pp.getTotalPages() )
{
%><a href="<%=path %>/page?page=<%=pp.getCurrentPage() + 1%>">下一页>></a>
<%
}
%>
<input type="text" name="input_text" id="input_text" size="1" />
<input type="button" name="skip" id="skip" value="跳转" onclick="skip();"/>
<script>
function skip(){
var v=document.getElementById("input_text").value;
location.href="page?page="+v;
}
</script>
</p>
</table>
</body>
</html>
初步看，感觉后台代码实在是繁琐，但这是考虑到程序健壮性与可移植性，方便代码重用。以后要用，根据自己的需要在属性文件（config.xml）中配置相关JDBC驱动，在jsp页面通过request获得后台Servlet（Page.jsp）的转发结果("result"),结合页面属性(PageProperties.java类)即可实现效果。
当然，这也是因为个人学习，倾向于多用点东西。
希望本文所述对大家jsp程序设计有所帮助。
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