JDBC实现JavaWeb分页
- JDBC工具类
package cn.rzpt.dbutil;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DBConnection {
private static String driver = "com.mysql.cj.jdbc.Driver";
private static String url = "jdbc:mysql://localhost:3306/world?serverTimezone=UTC";
private static String username = "root";
private static String password = "root";
static {
try {
/**
* 加载驱动
*/
Class.forName(driver);
}catch(Exception ex) {
ex.printStackTrace();
}
}
public static Connection getConnection() {
/**
* 创建连接对象
*/
Connection conn=null;
try {
conn=(Connection) DriverManager.getConnection(url,username,password);
}catch(Exception ex) {
ex.printStackTrace();
}
return conn;
}
/**
* 关闭相关流
*/
public static void closeAll(ResultSet rs,Statement st,Connection conn) {
try {
if(rs!=null) {
rs.close();
}
if(st!=null) {
st.close();
}
if(conn!=null) {
conn.close();
}
}catch(SQLException e) {
e.printStackTrace();
}
}
public static void closePst(ResultSet rs,PreparedStatement pst,Connection conn) {
try {
if(rs!=null) {
rs.close();
}
if(pst!=null) {
pst.close();
}
if(conn!=null) {
conn.close();
}
}catch(SQLException e) {
e.printStackTrace();
}
}
}
- 用户实体类
package cn.rzpt.entity;
public class User {
private String name;
private String passowrd;
public User() {
}
public User(String name, String passowrd) {
this.name = name;
this.passowrd = passowrd;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassowrd() {
return passowrd;
}
public void setPassowrd(String passowrd) {
this.passowrd = passowrd;
}
@Override
public String toString() {
return "User [name=" + name + ", passowrd=" + passowrd + "]";
}
}
- 分页信息的实体类
package cn.rzpt.entity;
import java.util.List;
/**
* 封装分页信息
* @author Administrator
*
*/
public class PageModel<E> {
//结果集
private List<E> list;
//查询记录数
private int totalRecords;
//每页多少条数据
private int pageSize;
//第几页
private int pageNo;
/**
* 总页数
* @return
*/
public int getTotalPages() {
// return (totalRecords + pageSize - 1) / pageSize;
return (totalRecords%pageSize==0?(totalRecords/pageSize):(totalRecords/pageSize+1));
}
/**
* 取得首页
* @return
*/
public int getTopPageNo() {
return 1;
}
/**
* 上一页
* @return
*/
public int getPreviousPageNo() {
if (pageNo <= 1) {
return 1;
}
return pageNo - 1;
}
/**
* 下一页
* @return
*/
public int getNextPageNo() {
if (pageNo >= getBottomPageNo()) {
return getBottomPageNo();
}
return pageNo + 1;
}
/**
* 取得尾页
* @return
*/
public int getBottomPageNo() {
return getTotalPages();
}
/**
* get set函数
* @return
*/
public List<E> getList() {
return list;
}
public void setList(List<E> list) {
this.list = list;
}
public int getTotalRecords() {
return totalRecords;
}
public void setTotalRecords(int totalRecords) {
this.totalRecords = totalRecords;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public int getPageNo() {
return pageNo;
}
public void setPageNo(int pageNo) {
this.pageNo = pageNo;
}
}
- Dao操作
package cn.rzpt.page;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import cn.rzpt.dbutil.DBConnection;
import cn.rzpt.entity.PageModel;
import cn.rzpt.entity.User;
public class PageDao {
public PageModel<User> findData(String pageNo,String pageSize){
PageModel<User> pageModel=null;
Connection conn=DBConnection.getConnection();
String sql="select * from user limit ?,?";
PreparedStatement pst=null;
ResultSet rs=null;
User user=null;
List<User> list=new ArrayList<User>();
try {
pst=conn.prepareStatement(sql);
//pstm.setInt(1, (pageNo-1)*pageSize);
//pstm.setInt(2, pageNo*pageSize);
pst.setInt(1, (Integer.parseInt(pageNo)-1)*Integer.parseInt(pageSize));
pst.setInt(2, Integer.parseInt(pageSize));
rs=pst.executeQuery();
while(rs.next()){
user=new User();
user.setName(rs.getString("name"));
user.setPassowrd(rs.getString("password"));
list.add(user);
}
//总的数据条数
ResultSet rs2=pst.executeQuery("select count(*) from user");
int total=0;
if(rs2.next()){
total=rs2.getInt(1);
}
pageModel=new PageModel<User>();
pageModel.setPageNo(Integer.parseInt(pageNo));
pageModel.setPageSize(Integer.parseInt(pageSize));
pageModel.setTotalRecords(total);
pageModel.setList(list);
} catch (SQLException e) {
e.printStackTrace();
}finally{
DBConnection.closePst(rs, pst, conn);
}
return pageModel;
}
}
- Servlet
package cn.rzpt.control;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.rzpt.entity.PageModel;
import cn.rzpt.entity.User;
import cn.rzpt.page.PageDao;
@WebServlet("/pageServlet")
public class PageServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
String pageSize = request.getParameter("pageSize");// 每页显示行数
String pageNo = request.getParameter("pageNo");// 当前显示页次
if (pageSize == null) {// 为空时设置默认页大小为10
pageSize = "10";
}
if (pageNo == null) {// 为空时设置默认为第1页
pageNo = "1";
}
//System.out.println("pageNo="+pageNo+"pageSize="+pageSize);
// 保存分页参数，传递给下一个页面
request.setAttribute("pageSize", pageSize);
request.setAttribute("pageNo", pageNo);
//新建Dao对象，获取pageModel
PageDao client=new PageDao();
PageModel<User> pageModel=client.findData(pageNo,pageSize);
request.setAttribute("pageModel", pageModel);//前端获取这个值
request.getRequestDispatcher("showinfo.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="pageServlet">
<input type="submit" value="查看所有用户信息">
</form>
</body>
</html>
<%@page import="cn.rzpt.entity.User" %>
<%@page import="cn.rzpt.entity.PageModel"%>
<%@page import="cn.rzpt.page.PageDao"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.util.*" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<%
String pageSize = (String) request.getAttribute("pageSize");
String pageNo = (String) request.getAttribute("pageNo");
PageModel<User> pageModel = (PageModel<User>)request.getAttribute("pageModel");
List<User> list=pageModel.getList();
%>
<body>
<table align="center" >
<tr>
<td align="center" colspan="3">
<h2>用户所有信息</h2>
</td>
</tr>
<tr align="center">
<td><b>用户名称</b></td>
<td><b>用户密码</b></td>
</tr>
<%
if(list==null||list.size()<1){
%><p align="center">还没有任何数据！</p>
<%}else{
for(User user:list){
%>
<tr>
<td><%=user.getName() %></td>
<td><%=user.getPassowrd()%></td>
</tr>
<%
}
}
%>
</table>
<form name="form1" action="pageServlet" method="post">
<TABLE border="0" width="100%" >
<TR>
<TD align="left"><a>每页条数</a>
<select name="pageSize"
onchange="document.all.pageNo.value='1';document.all.form1.submit();">
<option value="10" <%if(pageSize.equals("10")){%>
selected="selected" <%}%>>10</option>
<option value="20" <%if(pageSize.equals("20")){%>
selected="selected" <%}%>>20</option>
<option value="30" <%if(pageSize.equals("30")){%>
selected="selected" <%}%>>30</option>
</select></TD>
<TD align="right">
<a
href="javascript:document.all.pageNo.value='<%= pageModel.getTopPageNo() %>';document.all.form1.submit();">首页</a>
<a
href="javascript:document.all.pageNo.value='<%= pageModel.getPreviousPageNo() %>';document.all.form1.submit();">上一页</a>
<a
href="javascript:document.all.pageNo.value='<%= pageModel.getNextPageNo()%>';document.all.form1.submit();">下一页</a>
<a
href="javascript:document.all.pageNo.value='<%= pageModel.getBottomPageNo()%>';document.all.form1.submit();">尾页</a>
<a>第</a>
<select name="pageNo" onchange="document.all.form1.submit();">
<%
int pageCount = pageModel.getTotalPages();
%>
<%
for (int i = 1; i <= pageCount; i++) {
%>
<option value="<%=i%>" <%if(pageNo.equals(i+"")){%>
selected="selected" <%}%>><%=i%></option>
<%
}
%>
</select><a>页</a></TD>
</TR>
</TABLE>
</form>
</body>
</html>