Java学习之分页查询
一先做数据库的实体类
Userinfo.java
<span style="font-size:14px;">package com.zhu.books.jdbc;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class Pagation extends DBConnection {
public int getTableRsCount(){
int iCount=0; //记录行数，然后返回
try {
getConnection();
String sql="select count(id) as icount from table1";
pStmt=conn.prepareStatement(sql);
rs=pStmt.executeQuery();
if(rs.next()){
iCount=rs.getInt("icount");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return iCount;
}
/**
* 查询信息
*/
public List<Userinfo> getPageListUserinfo(int pageNum,int pageSize){
List<Userinfo> list=new ArrayList <Userinfo> ();
try {
getConnection();
int begin=(pageNum-1)*pageSize;
String sql="select * from table1 limit "+begin+","+pageSize;
pStmt=conn.prepareStatement(sql);
rs=pStmt.executeQuery();
while(rs.next()){
Userinfo user=new Userinfo();
user.setId(rs.getInt("id"));
user.setUname(rs.getString("uname"));
user.setRealname(rs.getString("realname"));
list.add(user);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return list;
}
</span><span style="font-size:18px;"><strong>}
</strong></span>
二:建立数据库连接
DBConnection.java
package com.zhu.books.jdbc;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
public class DBConnection {
private static final String CLS = "com.mysql.jdbc.Driver";
private static final String URL = "jdbc:mysql://localhost:3306/test";
private static final String USER = "root";
private static final String PWD = "122198";
public static Connection conn = null;
public static Statement stmt = null;
public static PreparedStatement pStmt = null;
public static ResultSet rs = null;
/**
* 建立数据库连接
*/
public static void getConnection(){
try{
Class.forName(CLS);
conn = DriverManager.getConnection(URL, USER, PWD);
}catch(Exception ex){
ex.printStackTrace();
}
}
/**
* 关闭连接
*/
public static void closeAll(){
try{
if(rs!=null){
rs.close();
rs=null;
}
if(stmt!=null){
stmt.close();
stmt=null;
}
if(pStmt!=null){
pStmt.close();
pStmt=null;
}
if(conn!=null){
conn.close();
conn=null;
}
}catch(Exception ex){
ex.printStackTrace();
}
}
}
三实施分页
Pagation.java
package com.zhu.books.jdbc;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class Pagation extends DBConnection {
public int getTableRsCount(){
int iCount=0; //记录行数，然后返回
try {
getConnection();
String sql="select count(id) as icount from table1";
pStmt=conn.prepareStatement(sql);
rs=pStmt.executeQuery();
if(rs.next()){
iCount=rs.getInt("icount");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return iCount;
}
/**
* 查询信息
*/
public List<Userinfo> getPageListUserinfo(int pageNum,int pageSize){
List<Userinfo> list=new ArrayList <Userinfo> ();
try {
getConnection();
int begin=(pageNum-1)*pageSize;
String sql="select * from table1 limit "+begin+","+pageSize;
pStmt=conn.prepareStatement(sql);
rs=pStmt.executeQuery();
while(rs.next()){
Userinfo user=new Userinfo();
user.setId(rs.getInt("id"));
user.setUname(rs.getString("uname"));
user.setRealname(rs.getString("realname"));
list.add(user);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return list;
}
}
四建立jsp查询页面
paging.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@page import="com.zhu.books.jdbc.Userinfo"%>
<%@page import="com.zhu.books.jdbc.Pagation"%>
<%
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>
<base href="<%=basePath%>">
<title>分页显示数据</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 border="1" align="center">
<tr>
<td>id</td>
<td>用户名</td>
<td>真实姓名 </td>
</tr>
<%
String strPagenum=request.getParameter("pageNum");
int pageNum=1;//当前列数
int pageSize=3;
int pageSum=0;
if(strPagenum!=null){
pageNum=Integer.parseInt(strPagenum);
}
Pagation pagation=new Pagation();
List<Userinfo> list=pagation.getPageListUserinfo(pageNum,pageSize);
int iCount=pagation.getTableRsCount();//记录总数
//计算总面积
pageSum=iCount/pageSize;
if(iCount%pageSize!=0){
pageSum+=1;
}
if(list.size()>0){
for(Userinfo user: list){
%>
<tr>
<td> <%=user.getId()%></td>
<td> <%=user.getUname()%></td>
<td> <%=user.getRealname()%></td>
</tr>
<%
}
}
%>
<tr>
<td colspan="3" align="center">
<%
out.print("第["+pageNum+"]页, 共["+pageSum+"]页");
if(pageNum<2){
%>
上一页
<%
}else{
%>
<a href="../Books/books/paging.jsp?pageNum=<%=pageNum-1%>" > 上一页</a>
<%
}
%>
<%
if(pageNum>=pageSum)
{
%>
上一页
<%
}else
{
%>
<a href="../Books/books/paging.jsp?pageNum=<%=pageNum+1 %>" >下 一页</a>
<%
} %>
</td>
</tr>
</table>
</body>
<span style="color:#ff0000;"></html>
</span>
页面展示
时间： 2024-08-27 02:09:20