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Java Web 簡(jiǎn)單的分頁(yè)顯示實(shí)例代碼

更新時(shí)間：2016年06月24日 09:30:03 作者：沒(méi)頭沒(méi)腦沒(méi)煩惱

這篇文章主要介紹了Java Web 簡(jiǎn)單的分頁(yè)顯示實(shí)例代碼的相關(guān)資料,本文通過(guò),計(jì)算總的頁(yè)數(shù)和查詢指定頁(yè)數(shù)據(jù)兩個(gè)方法實(shí)現(xiàn)分頁(yè)效果,非常不錯(cuò)，具有參考借鑒價(jià)值，需要的朋友可以參考下

本文通過(guò)兩個(gè)方法：（1）計(jì)算總的頁(yè)數(shù)。（2）查詢指定頁(yè)數(shù)據(jù)，實(shí)現(xiàn)簡(jiǎn)單的分頁(yè)效果。

思路：首先得在 DAO 對(duì)象中提供分頁(yè)查詢的方法，在控制層調(diào)用該方法查到指定頁(yè)的數(shù)據(jù)，在表示層通過(guò) EL 表達(dá)式和 JSTL 將該頁(yè)數(shù)據(jù)顯示出來(lái)。

先給大家展示下效果圖：

題外話：該分頁(yè)顯示是用 “表示層-控制層-DAO層-數(shù)據(jù)庫(kù)”的設(shè)計(jì)思想實(shí)現(xiàn)的，有什么需要改進(jìn)的地方大家提出來(lái)，共同學(xué)習(xí)進(jìn)步。廢話不多說(shuō)了，開(kāi)始進(jìn)入主題，詳細(xì)步驟如下所示：

1.DAO層-數(shù)據(jù)庫(kù)

JDBCUtils 類用于打開(kāi)和關(guān)閉數(shù)據(jù)庫(kù)，核心代碼如下：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class JDBCUtils {
private Connection conn=null;
private PreparedStatement pstmt=null; 
/**
* connect 連接數(shù)據(jù)庫(kù)
* @return
*/
public Connection connect(){
String user="root";
String password="1234";
String driverClass = "com.mysql.jdbc.Driver";
String jdbcUrl = "jdbc:mysql://localhost:3306/book";
try {
Class.forName(driverClass);
conn = DriverManager.getConnection(jdbcUrl, user, password);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
/**
* close 關(guān)閉數(shù)據(jù)庫(kù)
* @param conn
* @param pstmt
* @param resu
*/
public void close(Connection conn,PreparedStatement pstmt,ResultSet result){
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
}
}
if(pstmt != null){
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(result != null){
try {
result.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}

UserDao 類中的方法 getPage() 和方法 listUser() 分別用來(lái)計(jì)算總頁(yè)數(shù)和查詢指定頁(yè)的數(shù)據(jù)，核心代碼如下：

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.db.JDBCUtils;
public class UserDao {
/**
* 計(jì)算總的頁(yè)數(shù)
* @return
*/
public int getPage(){
int recordCount=0,t1=0,t2=0;
PreparedStatement pstmt=null;
ResultSet result=null;
JDBCUtils jdbc=new JDBCUtils();
Connection conn=jdbc.connect();
String sql="select count(*) from books";
try {
pstmt=conn.prepareStatement(sql);
result=pstmt.executeQuery();
result.next();
recordCount=result.getInt(1);
t1=recordCount%5;
t2=recordCount/5;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
jdbc.close(conn, pstmt, result);
}
if(t1 != 0){
t2=t2+1;
}
return t2;
}
/**
* 查詢指定頁(yè)的數(shù)據(jù)
* @param pageNo
* @return
*/
public List<User> listUser(int pageNo){
PreparedStatement pstmt=null;
ResultSet result=null;
List<User> list=new ArrayList<User>();
int pageSize=5;
int page=(pageNo-1)*5;
JDBCUtils jdbc=new JDBCUtils();
Connection conn=jdbc.connect();
String sql="select * from books order by id limit ?,?";
try {
pstmt=conn.prepareStatement(sql);
pstmt.setInt(1, page);
pstmt.setInt(2, pageSize);
result=pstmt.executeQuery();
while(result.next()){
User user=new User();
user.setId(result.getInt(1));
user.setName(result.getString(2));
user.setNumber(result.getString(3));
list.add(user);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
jdbc.close(conn, pstmt, result);
}
return list;
}
}

User 類用于存儲(chǔ)查詢到的數(shù)據(jù)，核心代碼如下：

public class User {
private int id;
private String name;
private String number;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
}

2.控制層

ListUser 類內(nèi)部調(diào)用 UserDao 對(duì)象查詢數(shù)據(jù)并指派頁(yè)面顯示數(shù)據(jù)，核心代碼如下：

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dao.User;
import com.dao.UserDao;
public class ListUser extends HttpServlet {
public ListUser() {
super();
}
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("utf-8");
int pageNo = 1;
UserDao userdao=new UserDao();
List<User> lists=new ArrayList<User>();
String pageno=request.getParameter("pageNos");
if(pageno != null){
pageNo=Integer.parseInt(pageno);
}
lists=userdao.listUser(pageNo);
int recordCount=userdao.getPage();
request.setAttribute("recordCount", userdao.getPage());
request.setAttribute("listss", lists);
request.setAttribute("pageNos", pageNo);
request.getRequestDispatcher("userlist.jsp").forward(request, response);
}
public void init() throws ServletException {
// Put your code here
}
}

3.表示層

輸出頁(yè)面 userlist.jsp ,使用 EL 和 JSTL 輸出查詢結(jié)果，核心代碼如下：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%> 
<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn"%>
<%
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>My JSP 'userlist.jsp' starting page</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">
-->
<style type="text/css">
th,td{width: 150px;border: 2px solid gray;text-align: center;}
body{text-align: center;}
a{text-decoration: none;}
table {border-collapse: collapse;}
</style>
</head>
<body>
<h2 align="center">圖書(shū)信息</h2>
<table align="center">
<tr><td>書(shū)號(hào)</td><td>書(shū)名</td><td>庫(kù)存量</td></tr>
</table>
<table align="center">
<c:forEach items="${listss}" var="person">
<tr>
<td class="hidden-480">${person.id}</td>
<td class="hidden-480">${person.name }</td>
<td class="hidden-480">${person.number }</td>
</tr>
</c:forEach>
</table>
<br>
<c:if test="${pageNos>1 }">
<a href="ListUser?pageNos=1" >首頁(yè)</a>
<a href="ListUser?pageNos=${pageNos-1 }">上一頁(yè)</a>
</c:if>
<c:if test="${pageNos <recordCount }">
<a href="ListUser?pageNos=${pageNos+1 }">下一頁(yè)</a>
<a href="ListUser?pageNos=${recordCount }">末頁(yè)</a>
</c:if>
<form action="ListUser">
<h4 align="center">共${recordCount}頁(yè) &nbsp
<input type="text" value="${pageNos}" name="pageNos" size="1">頁(yè)
<input type="submit" value="到達(dá)">
</h4>
</form>
</body>
</html>

以上所述是小編給大家介紹的Java Web 簡(jiǎn)單的分頁(yè)顯示實(shí)例代碼，希望對(duì)大家有所幫助，如果大家有任何疑問(wèn)請(qǐng)給我留言，小編會(huì)及時(shí)回復(fù)大家的。在此也非常感謝大家對(duì)腳本之家網(wǎng)站的支持！

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