jsp+servlet+javabean实现数据分页

第一次写博文，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

jsp+servlet+javabean实现数据分页

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！

jsp+servlet+javabean实现数据分页

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。

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jsp+servlet+javabean实现数据分页

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