jsp+servlet+javabean实现数据分页方法完整实例
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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