JavaWeb入門教程之分頁(yè)查詢功能的簡(jiǎn)單實(shí)現(xiàn)
更新時(shí)間：2020年11月22日 09:13:12 作者：沂牛教育
這篇文章主要介紹了JavaWeb入門教程之分頁(yè)查詢功能的簡(jiǎn)單實(shí)現(xiàn)，文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧
一、MySql實(shí)現(xiàn)分頁(yè)查詢的SQL語句
1、分頁(yè)需求：
客戶端通過傳遞pageNo(頁(yè)碼)，counter(每頁(yè)顯示的條數(shù))兩個(gè)參數(shù)去分頁(yè)查詢數(shù)據(jù)庫(kù)表中的數(shù)據(jù)，那我們知道MySql數(shù)據(jù)庫(kù)提供了分頁(yè)的函數(shù)limit m,n，但是該函數(shù)的用法和我們的需求不一樣，所以就需要我們根據(jù)實(shí)際情況去改寫適合我們自己的分頁(yè)語句，具體的分析如下：
比如：
查詢第1條到第10條的數(shù)據(jù)的sql是：select * from table limit 0,10; ->對(duì)應(yīng)我們的需求就是查詢第一頁(yè)的數(shù)據(jù)：select * from table limit (1-1)*10,10;
查詢第10條到第20條的數(shù)據(jù)的sql是：select * from table limit 10,20; ->對(duì)應(yīng)我們的需求就是查詢第二頁(yè)的數(shù)據(jù)：select * from table limit (2-1)*10,10;
查詢第20條到第30條的數(shù)據(jù)的sql是：select * from table limit 20,30; ->對(duì)應(yīng)我們的需求就是查詢第三頁(yè)的數(shù)據(jù)：select * from table limit (3-1)*10,10;
2、總結(jié)
通過上面的分析，可以得出符合我們自己需求的分頁(yè)sql格式是：select * from table limit (pageNo-1)*counter,counter; 其中pageNo是頁(yè)碼，counter是每頁(yè)顯示的條數(shù)。
二、JavaWeb程序
1、創(chuàng)建PageBeanUtils.java工具類
package com.ambow.utils;
import java.util.List;
public class PageBeanUtils<T> {
private int prePage;//上一頁(yè)
private int nextPage;//下一頁(yè)
private int firstPage=1;//首頁(yè)
private int lastPage;//尾頁(yè)
private int currentPage = 1;//當(dāng)前
private int totalPage;//總頁(yè)數(shù)
private int pageSize;//每頁(yè)顯示條數(shù)，默認(rèn)顯示10條
private int totalData;//數(shù)據(jù)總條數(shù)
private List<T> pageData;//數(shù)據(jù)
public PageBeanUtils(int currentPage,int pageSize, int totalData) {
this.currentPage = currentPage;
this.pageSize = pageSize;
this.totalData = totalData;
//計(jì)算獲得總頁(yè)數(shù)（尾頁(yè)）
// this.totalPage = this.lastPage = (totalData+pageSize-1)/pageSize;
this.totalPage = this.lastPage = (int)Math.ceil((double)totalData/pageSize);
//防止當(dāng)前頁(yè)小于1
this.currentPage = Math.max(this.currentPage, 1);
//防止當(dāng)前頁(yè)大于總的頁(yè)數(shù)
this.currentPage = Math.min(this.totalPage, this.currentPage);
//設(shè)置上一頁(yè)，上一頁(yè)不能小于1
this.prePage = Math.max(this.currentPage-1, 1);
//設(shè)置下一頁(yè)，下一頁(yè)不能大于總頁(yè)數(shù)
this.nextPage = Math.min(this.currentPage+1, this.totalPage);
/**
* ceil
public static double ceil(double a)
返回最小的（最接近負(fù)無窮大） double 值，該值大于等于參數(shù)，并等于某個(gè)整數(shù)。特殊情況如下：
如果參數(shù)值已經(jīng)等于某個(gè)整數(shù)，那么結(jié)果與該參數(shù)相同。
如果參數(shù)為 NaN、無窮大、正 0 或負(fù) 0，那么結(jié)果與參數(shù)相同。
如果參數(shù)值小于 0，但是大于 -1.0，那么結(jié)果為負(fù) 0。
注意， Math.ceil(x) 的值與 -Math.floor(-x) 的值完全相同。
參數(shù)：
a - 一個(gè)值。
返回：
最小（最接近負(fù)無窮大）浮點(diǎn)值，該值大于等于該參數(shù)，并等于某個(gè)整數(shù)。
*/
}
public PageBeanUtils(int prePage, int nextPage, int firstPage, int lastPage, int currentPage, int totalPage,
int pageSize, int totalData, List<T> pageData) {
super();
this.prePage = prePage;
this.nextPage = nextPage;
this.firstPage = firstPage;
this.lastPage = lastPage;
this.currentPage = currentPage;
this.totalPage = totalPage;
this.pageSize = pageSize;
this.totalData = totalData;
this.pageData = pageData;
}
public int getPrePage() {
return prePage;
}
public void setPrePage(int prePage) {
this.prePage = prePage;
}
public int getNextPage() {
return nextPage;
}
public void setNextPage(int nextPage) {
this.nextPage = nextPage;
}
public int getFirstPage() {
return firstPage;
}
public void setFirstPage(int firstPage) {
this.firstPage = firstPage;
}
public int getLastPage() {
return lastPage;
}
public void setLastPage(int lastPage) {
this.lastPage = lastPage;
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getTotalPage() {
return totalPage;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public int getTotalData() {
return totalData;
}
public void setTotalData(int totalData) {
this.totalData = totalData;
}
public List<T> getPageData() {
return pageData;
}
public void setPageData(List<T> pageData) {
this.pageData = pageData;
}
/*
*
*
* totalPage = (totalData+pageSize-1)/pageSize;
*
*
* */
}
2、在接口里面定義分頁(yè)查詢的方法
package com.ambow.dao;
import java.util.List;
import com.ambow.pojo.Good;
public interface IGoodDao {
//增刪改查
public void add(Good good);
public void delete(Good good);
public void update(Good good);
public void query(Good good);
public Good queryOne(Good good);
public List<Good> queryMore(Good good);
public List<Good> queryByName(String name);//根據(jù)商家名稱進(jìn)行模糊查詢
//條件分頁(yè)查詢
public List<Good> queryByName(String name,int currentPage,int pageSize);
//獲取滿足某個(gè)條件的總記錄數(shù)
public int getTotalNum(String name);
}
3、在接口的實(shí)現(xiàn)類里面實(shí)現(xiàn)方法
package com.ambow.dao.impl;
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 com.ambow.dao.IGoodDao;
import com.ambow.pojo.Good;
import com.ambow.utils.DBUtils;
public class GoodDaoImpl implements IGoodDao {
DBUtils db = new DBUtils();
@Override
public void add(Good good) {
Connection conn = null;
PreparedStatement pstmt = null;
String sql = "insert into good (name,address,tel,dishes) values (?,?,?,?)";
try {
conn = DBUtils.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, good.getName());
pstmt.setString(2, good.getAddress());
pstmt.setString(3, good.getTel());
pstmt.setString(4, good.getDishes());
int isOk = pstmt.executeUpdate();
//System.out.println("add-----"+isOk);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void delete(Good good) {
Connection conn = null;
PreparedStatement pstmt = null;
String sql = "delete from good where id = ?";
try {
conn = DBUtils.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, good.getId());
int isOk = pstmt.executeUpdate();
System.out.println("delete-----"+isOk);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void update(Good good) {
Connection conn = null;
PreparedStatement pstmt = null;
String sql = "update good set name=?,address=?,tel=?,dishes=? where id=?";
try {
conn = DBUtils.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, good.getName());
pstmt.setString(2, good.getAddress());
pstmt.setString(3, good.getTel());
pstmt.setString(4, good.getDishes());
pstmt.setInt(5,good.getId());
int isOk = pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void query(Good good) {
// TODO Auto-generated method stub
}
@Override
public Good queryOne(Good good) {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql = "select * from good where id = ?";
Good gd = null;
try {
conn = DBUtils.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, good.getId());
rs = pstmt.executeQuery();
while(rs.next()){
gd = new Good(rs.getInt(1),rs.getString(2),rs.getString(3),
rs.getString(4),rs.getString(5));
}
} catch (SQLException e) {
e.printStackTrace();
}
return gd;
}
@Override
public List<Good> queryMore(Good good) {
// TODO Auto-generated method stub
return null;
}
@Override
public List<Good> queryByName(String name) {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql = "select * from good where name like ?";
List<Good> goodList = new ArrayList<Good>();
try {
conn = DBUtils.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, "%"+name+"%");
rs = pstmt.executeQuery();
while(rs.next()){
goodList.add(new Good(rs.getInt(1),rs.getString(2),rs.getString(3),
rs.getString(4),rs.getString(5)));
}
} catch (SQLException e) {
e.printStackTrace();
}
return goodList;
}
@Override
public List<Good> queryByName(String name, int currentPage, int pageSize) {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql = "select * from good where name like ? limit ?,?";
List<Good> goodList = new ArrayList<Good>();
try {
conn = DBUtils.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, "%"+name+"%");
pstmt.setInt(2,(currentPage-1)*pageSize);
pstmt.setInt(3,pageSize);
rs = pstmt.executeQuery();
while(rs.next()){
goodList.add(new Good(rs.getInt(1),rs.getString(2),rs.getString(3),
rs.getString(4),rs.getString(5)));
}
} catch (SQLException e) {
e.printStackTrace();
}
return goodList;
}
@Override
public int getTotalNum(String name) {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql = "select count(id) from good where name like ?";
int total = 0;
try {
conn = DBUtils.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, "%"+name+"%");
rs = pstmt.executeQuery();
while(rs.next()){
total = rs.getInt(1);
}
} catch (SQLException e) {
e.printStackTrace();
}
return total;
}
}
4.在Servlet里面調(diào)用實(shí)現(xiàn)類里面的分頁(yè)查詢方法
package com.ambow.servlet;
import java.io.IOException;
import java.util.List;
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 com.ambow.dao.IGoodDao;
import com.ambow.dao.impl.GoodDaoImpl;
import com.ambow.pojo.Good;
import com.ambow.utils.PageBeanUtils;
@WebServlet("/QueryServlet")
public class QueryServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private IGoodDao goodDao = new GoodDaoImpl();
public QueryServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
String keywords = request.getParameter("kw");
String method = request.getParameter("method");
if("add".equals(method)){
String name = request.getParameter("name");
String address = request.getParameter("address");
String tel = request.getParameter("tel");
String dishes = request.getParameter("dishes");
Good good = new Good(0,name,address,tel,dishes);
goodDao.add(good);
//調(diào)用dao的查詢方法，返回一個(gè)List
List<Good> goods = goodDao.queryByName(keywords);
request.setAttribute("list", goods);
request.getRequestDispatcher("goods.jsp").forward(request, response);
}else if("search".equals(method)){
if(null==keywords) {
keywords="";
}
int currentPage = 1;
try {
currentPage=Integer.parseInt(request.getParameter("curPage"));
if(currentPage<=0) {
currentPage = 1;
}
}catch(Exception e) {
currentPage = 1;
}
int pageSize=10;
int totalData = goodDao.getTotalNum(keywords);
int totalPage = (int)Math.ceil((double)totalData/pageSize);
if(currentPage>totalPage){
currentPage = totalPage;
}
List<Good> goods = goodDao.queryByName(keywords,currentPage,pageSize);
PageBeanUtils pg = new PageBeanUtils(currentPage,pageSize,totalData);
pg.setPageData(goods);
request.setAttribute("pg", pg);
request.getRequestDispatcher("good2.jsp").forward(request, response);
}else if("delete".equals(method)){
System.out.println(keywords);
//實(shí)現(xiàn)刪除
String id = request.getParameter("id");
Good good = new Good();
good.setId(Integer.valueOf(id));
goodDao.delete(good);
//調(diào)用dao的查詢方法，返回一個(gè)List
List<Good> goods = goodDao.queryByName(keywords);
request.setAttribute("list", goods);
request.getRequestDispatcher("goods.jsp").forward(request, response);
}else if("queryById".equals(method)){
//查詢一個(gè)
String id = request.getParameter("id");
Good good = new Good();
good.setId(Integer.valueOf(id));
good = goodDao.queryOne(good);
//調(diào)用dao的查詢方法，返回一個(gè)good
request.setAttribute("good", good);
request.getRequestDispatcher("update.jsp").forward(request, response);
}else if("update".equals(method)){
String id = request.getParameter("id");
String name = request.getParameter("name");
String address = request.getParameter("address");
String tel = request.getParameter("tel");
String dishes = request.getParameter("dishes");
Good good = new Good(Integer.valueOf(id),name,address,tel,dishes);
goodDao.update(good);
//調(diào)用dao的查詢方法，返回一個(gè)List
List<Good> goods = goodDao.queryByName(keywords);
request.setAttribute("list", goods);
request.getRequestDispatcher("goods.jsp").forward(request, response);
}else{
//調(diào)用dao的查詢方法，返回一個(gè)List
List<Good> goods = goodDao.queryByName(keywords);
request.setAttribute("list", goods);
request.getRequestDispatcher("goods.jsp").forward(request, response);
}
}
}
5.在JSP頁(yè)面獲取Servlet里面?zhèn)鬟^來的數(shù)據(jù)
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8" import="java.util.ArrayList,com.ambow.pojo.Good,
com.ambow.pojo.User,com.ambow.utils.PageBeanUtils"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>外賣系統(tǒng)的搜索功能</title>
</head>
<body>
<form action="QueryServlet?method=search" method="POST">
<input type="text" name="kw"/><input type="submit" value="搜索"/><a href=" ">添加商家</a >
<table border="1">
<tr><th>商家店名</th><th>商家地址</th><th>商家電話</th><th>經(jīng)營(yíng)菜品</th><th colspan="2">編輯</th></tr>
<c:forEach items="${pg.pageData}" var="g">
<tr><td>${g.name}</td><td>${g.address}</td><td>${g.tel}</td><td>${g.dishes}</td>
<td><a href="QueryServlet?method=queryById&id=${g.id}">修改</a ></td>
<td><a href="QueryServlet?method=delete&id=${g.id}" onClick="return confirm('確認(rèn)刪除本條數(shù)據(jù)嗎？');">刪除</a ></td></tr>
</c:forEach>
</table>
<a href="QueryServlet?method=search&curPage=${pg.firstPage}">首頁(yè)</a >
<a href="QueryServlet?method=search&curPage=${pg.currentPage - 1}">上一頁(yè)</a >
<a href="QueryServlet?method=search&curPage=${pg.currentPage + 1}">下一頁(yè)</a >
<a href="QueryServlet?method=search&curPage=${pg.lastPage}">尾頁(yè)</a >
當(dāng)前第${pg.currentPage}頁(yè)/共${pg.totalPage}頁(yè)
每頁(yè)顯示${pg.pageSize}條
</form>
</body>
</html>
總結(jié)
到此這篇關(guān)于JavaWeb入門教程之分頁(yè)查詢功能的文章就介紹到這了,更多相關(guān)JavaWeb分頁(yè)查詢功能內(nèi)容請(qǐng)搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！
相關(guān)文章
Jenkins節(jié)點(diǎn)配置實(shí)現(xiàn)原理及過程解析
這篇文章主要介紹了Jenkins節(jié)點(diǎn)配置實(shí)現(xiàn)原理及過程解析,文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值,需要的朋友可以參考下2020-09-09
spring使用Filter過濾器對(duì)Response返回值進(jìn)行修改的方法
這篇文章主要介紹了spring使用Filter過濾器對(duì)Response返回值進(jìn)行修改,本文通過實(shí)例代碼給大家介紹的非常詳細(xì),對(duì)大家的學(xué)習(xí)或工作具有一定的參考借鑒價(jià)值,需要的朋友可以參考下2023-09-09
Java8 LocalDateTime極簡(jiǎn)時(shí)間日期操作小結(jié)
這篇文章主要介紹了Java8-LocalDateTime極簡(jiǎn)時(shí)間日期操作整理,通過實(shí)例代碼給大家介紹了java8 LocalDateTime 格式化問題，需要的朋友可以參考下2020-04-04
高并發(fā)下restTemplate的錯(cuò)誤分析方式
這篇文章主要介紹了高并發(fā)下restTemplate的錯(cuò)誤分析方式，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。如有錯(cuò)誤或未考慮完全的地方，望不吝賜教2021-10-10
避免多個(gè)jar通過maven打包導(dǎo)致同名配置文件覆蓋沖突問題
這篇文章主要介紹了避免多個(gè)jar通過maven打包導(dǎo)致同名配置文件覆蓋沖突問題，有需要的朋友可以借鑒參考下，希望能夠有所幫助，祝大家多多進(jìn)步，早日升職加薪2023-05-05
這篇文章主要介紹了SpringBoot 策略模式的實(shí)踐使用，幫助大家更好的理解和學(xué)習(xí)使用SpringBoot，感興趣的朋友可以了解下2021-04-04
簡(jiǎn)單了解JavaCAS的相關(guān)知識(shí)原理
這篇文章主要介紹了簡(jiǎn)單了解JavaCAS的相關(guān)知識(shí),文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值,需要的朋友可以參考下2019-11-11
SpringBoot集成WebSocket長(zhǎng)連接實(shí)際應(yīng)用詳解
這篇文章主要介紹了SpringBoot集成WebSocket長(zhǎng)連接實(shí)際應(yīng)用詳解，文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧2020-06-06
java實(shí)現(xiàn)漢字轉(zhuǎn)unicode與漢字轉(zhuǎn)16進(jìn)制實(shí)例
這篇文章主要介紹了java實(shí)現(xiàn)漢字轉(zhuǎn)unicode與漢字轉(zhuǎn)16進(jìn)制的實(shí)現(xiàn)方法,是Java操作漢字編碼轉(zhuǎn)換的一個(gè)典型應(yīng)用,非常具有實(shí)用價(jià)值,需要的朋友可以參考下2014-10-10
本篇文章給大家分析了Java隨機(jī)數(shù)與定時(shí)器的實(shí)現(xiàn)原理以及代碼分享，有需要的讀者參考下吧。2018-02-02