java分页技术实现详解

1.编写通用的分页工具

public class PageUtil {

/*参数需要页面传入*/

private Integer pageSize=10;//每页显式多少条记录

private Integer currentPage=1;//当前页号

/*参数需要从数据查询*/

private Integer allRowsAmount=0;//总记录数

private List<?> items;//记录集合

/*这些参数由计算得出*/

private Integer allPageAmount;//总页数

private Integer currentPageStartRow=1;//当前页面的开始行

private Integer currentPageEndRow;//当前页面的结束行

private Integer firstPage=1;//首页的页号

private Integer lastPage;//末页的页号

private Integer prevPage;//上一页页号

private Integer nextPage;//下一页页号

private Integer startPageNum;//导航开始页号

private Integer endPageNum;//导航结束页号

private Integer maxPageAmount =10;//最多显示多少页

public List<Integer> showPageNums =new ArrayList<Integer>();//要显示的页号

public PageUtil() {

super();

// TODO Auto-generated constructor stub

}

/*设置当前页*/

public void setCurrentPage(int currentPage){

if(currentPage <1){

this.currentPage=1;

}else{

this.currentPage=currentPage;

}

}

/*设置每页记录数，默认10条*/

public void setPageSize(int pageSize) {

this.pageSize = pageSize;

}

/*设置总记录数*/

public void setAllRowsAmount(int allRowsAmount) {

this.allRowsAmount = allRowsAmount;

}

/*设置分页内容*/

public void setItems(List<?> items) {

this.items = items;

}

/*设置导航页数量*/

public void setMaxPageAmount(int maxPageAmount) {

this.maxPageAmount = maxPageAmount;

}

public void calculatePage(){

//计算总页数

if(this.allRowsAmount % this.pageSize ==0){

this.allPageAmount=this.allRowsAmount/this.pageSize;

}else{

this.allPageAmount=this.allRowsAmount/this.pageSize+1;

}

//设置首页

this.firstPage=1;

//设置末页

this.lastPage=this.allPageAmount;

if(this.currentPage *pageSize <allRowsAmount){

this.currentPageEndRow =this.currentPage*pageSize;

this.currentPageStartRow =(this.currentPage-1)*pageSize+1;

}else{

this.currentPageEndRow =this.allRowsAmount;

this.currentPageStartRow =(this.allPageAmount-1)*pageSize+1;

if(this.currentPageStartRow <0){

this.currentPageStartRow=0;

}

}

//设置前一页

if(this.currentPage >1){

this.prevPage=this.currentPage-1;

}else{

this.prevPage=this.currentPage;

}

//设置下一页

if(this.currentPage <this.lastPage){

this.nextPage=this.currentPage+1;

}else{

this.nextPage=this.lastPage;

}

//计算数字导航页

startPageNum =Math.max(this.currentPage-maxPageAmount/2, firstPage);

endPageNum =Math.min(startPageNum+maxPageAmount, lastPage);

if(endPageNum-startPageNum <maxPageAmount){

startPageNum =Math.max(endPageNum -maxPageAmount , 1);

}

for(int i=startPageNum ;i<=endPageNum;i++){

showPageNums.add(i);

}

}

//以下get方法是对外提供的方法用来获取参数值

public Integer getPageSize() {

return pageSize;

}

public Integer getCurrentPage() {

return currentPage;

}

public Integer getAllRowsAmount() {

return allRowsAmount;

}

public List<?> getItems() {

return items;

}

public Integer getAllPageAmount() {

return allPageAmount;

}

public Integer getCurrentPageStartRow() {

return currentPageStartRow;

}

public Integer getCurrentPageEndRow() {

return currentPageEndRow;

}

public Integer getFirstPage() {

return firstPage;

}

public Integer getLastPage() {

return lastPage;

}

public Integer getPrevPage() {

return prevPage;

}

public Integer getNextPage() {

return nextPage;

}

public Integer getStartPageNum() {

return startPageNum;

}

public Integer getEndPageNum() {

return endPageNum;

}

public Integer getMaxPageAmount() {

return maxPageAmount;

}

public List<Integer> getShowPageNums() {

return showPageNums;

}

@Override

public String toString() {

return "PageUtil [pageSize=" + pageSize + ", currentPage="

+ currentPage + ", allRowsAmount=" + allRowsAmount + ", 每页内容items="

+ items + ", allPageAmount=" + allPageAmount

+ ", currentPageStartRow=" + currentPageStartRow

+ ", currentPageEndRow=" + currentPageEndRow + ", firstPage="

+ firstPage + ", lastPage=" + lastPage + ", prevPage="

+ prevPage + ", nextPage=" + nextPage + ", startPageNum="

+ startPageNum + ", endPageNum=" + endPageNum + ", maxPageAmount="

+ maxPageAmount + ", 页号list=" + showPageNums + "]";

}

public static void main(String[] args) {

List<String> items =new ArrayList<String>();

for(int i=0;i<10;i++){

items.add("str"+i);

}

PageUtil pageUtil =new PageUtil();

pageUtil.setCurrentPage(1);

//pageUtil.setItems(items);

pageUtil.setAllRowsAmount(33);

pageUtil.calculatePage();

System.out.println(pageUtil);

}

}

2.servlet+c3p0+mysql实现分页

工程目录：




环境搭建：

<dependencies>

<dependency>

<groupId>junit</groupId>

<artifactId>junit</artifactId>

<version>3.8.1</version>

<scope>test</scope>

</dependency>

<dependency>

<groupId>com.mchange</groupId>

<artifactId>c3p0</artifactId>

<version>0.9.2.1</version>

</dependency>

<dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

<version>5.1.22</version>

</dependency>

<dependency>

<groupId>javax.servlet</groupId>

<artifactId>jstl</artifactId>

<version>1.2</version>

</dependency>

</dependencies>

c3p0配置文件：

<c3p0-config>

<!-- 默认配置 -->

<default-config>

<property name="jdbcUrl">jdbc:mysql://localhost:3306/basicjdbc?characterEncoding=utf-8</property>

<property name="driverClass">com.mysql.jdbc.Driver</property>

<property name="user">root</property>

<property name="password"></property>

<property name="initialPoolSize">3</property>

<property name="maxPoolSize">6</property>

<property name="maxIdleTime">1000</property>

</default-config>

<!-- 以下的配置用于个人需要再配置 -->

<name-config name="my_config">

<property name="jdbcUrl">jdbc:mysql://localhost:3306/basicjdbc?characterEncoding=utf-8</property>

<property name="driverClass">com.mysql.jdbc.Driver</property>

<property name="user">root</property>

<property name="password"></property>

<property name="initialPoolSize">3</property>

<property name="maxPoolSize">6</property>

<property name="maxIdleTime">1000</property>

</name-config>

</c3p0-config>

使用c3p0连接池的工具类：

public class DbUtil {

private static DataSource dataSource=null;

static{

dataSource=new ComboPooledDataSource();

}

public static Connection getConnection(){

try{

return dataSource.getConnection();

}catch(SQLException e){

throw new RuntimeException(e);

}

}

//释放对象的连接

public static void close(Connection conn,Statement stmt,ResultSet rs){

if(rs !=null){

try{

rs.close();

}catch(SQLException e){

e.printStackTrace();

throw new RuntimeException(e);

}

}

if(stmt !=null){

try{

stmt.close();

}catch(SQLException e){

e.printStackTrace();

throw new RuntimeException(e);

}

}

if(conn !=null){

try{

conn.close();

}catch(SQLException e){

e.printStackTrace();

throw new RuntimeException(e);

}

}

}

public static void main(String[] args) throws Exception{

String sql="select id,username,gender from myuser limit 3,10";

Connection conn =DbUtil.getConnection();

PreparedStatement ps =conn.prepareStatement(sql);

ResultSet rs =ps.executeQuery();

while(rs.next()){

String id =rs.getString("id");

String username =rs.getString("username");

String gender =rs.getString("gender");

System.out.println(id+","+username+","+gender);

}

DbUtil.close(conn,ps,rs);

}

}

dao层：主要是获取记录的总数便于计算其他值，还有就是获取每页显示的数据。

public class UserDaoImpl implements IUserDao{

//从数据库查询记录的总条数

public Integer getAllRowsAmount() throws Exception{

String sql="select count(*) from myuser";

Connection conn =DbUtil.getConnection();

PreparedStatement pstmt =conn.prepareStatement(sql);

ResultSet rs =pstmt.executeQuery();

Integer allRowsAmount=0;

if(rs.next()){

allRowsAmount =rs.getInt("count(*)");

}

DbUtil.close(conn, pstmt, rs);

return allRowsAmount;

}

//通过当前页号查询条件记录

public List<User> getUserByCurrentPage(Integer currentPageStartRow, Integer pageSize) throws Exception{

String sql="select id,username,gender from myuser limit "+(currentPageStartRow-1)+","+pageSize;

Connection conn =DbUtil.getConnection();

PreparedStatement pstmt =conn.prepareStatement(sql);

ResultSet rs =pstmt.executeQuery();

List<User> list =new ArrayList<User>();

while(rs.next()){

User user =new User();

user.setId(rs.getInt("id"));

user.setUsername(rs.getString("username"));

user.setGender(rs.getString("gender"));

list.add(user);

}

DbUtil.close(conn, pstmt, rs);

return list;

}

public static void main(String[] args) throws Exception {

UserDaoImpl userDaoImpl =new UserDaoImpl();

PageUtil pageUtil =new PageUtil();

pageUtil.setAllRowsAmount(userDaoImpl.getAllRowsAmount());

pageUtil.calculatePage();

for(User user :userDaoImpl.getUserByCurrentPage(pageUtil.getStartPageNum(), pageUtil.getPageSize())){

System.out.println(user.getId()+","+user.getUsername()+","+user.getGender());

}

System.out.println(userDaoImpl.getAllRowsAmount());

}

}

dao接口：

public interface IUserDao {

public Integer getAllRowsAmount() throws Exception;

public List<User> getUserByCurrentPage(Integer currentPageStartRow, Integer pageSize) throws Exception;

}

model类：

User.java：

public class User {

private int id;

private String username;

private String gender;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getGender() {

return gender;

}

public void setGender(String gender) {

this.gender = gender;

}

}

页面显示的模型Page.java：

public class Page {

private Integer currentPage;

private Integer prevPage;

private Integer nextPage;

private List<User> showUsers =new ArrayList<User>();

private List<Integer> showPageNums =new ArrayList<Integer>();

public Integer getCurrentPage() {

return currentPage;

}

public void setCurrentPage(Integer currentPage) {

this.currentPage = currentPage;

}

public Integer getPrevPage() {

return prevPage;

}

public void setPrevPage(Integer prevPage) {

this.prevPage = prevPage;

}

public Integer getNextPage() {

return nextPage;

}

public void setNextPage(Integer nextPage) {

this.nextPage = nextPage;

}

public List<User> getShowUsers() {

return showUsers;

}

public void setShowUsers(List<User> showUsers) {

this.showUsers = showUsers;

}

public List<Integer> getShowPageNums() {

return showPageNums;

}

public void setShowPageNums(List<Integer> showPageNums) {

this.showPageNums = showPageNums;

}

}

service层：通过页面传入当前页号数据，来查询需要的值。

UserService.java：

public class UserServiceImpl implements IUserService{

private IUserDao userDao =new UserDaoImpl();

public Page pageUsers(String currentPage) throws Exception{

int allRowsAmount =userDao.getAllRowsAmount();

PageUtil pageUtil =new PageUtil();

pageUtil.setAllRowsAmount(allRowsAmount);

if(currentPage !=null){

pageUtil.setCurrentPage(Integer.parseInt(currentPage));

}

pageUtil.calculatePage();

List<User> list =userDao.getUserByCurrentPage(pageUtil.getCurrentPageStartRow(), pageUtil.getPageSize());

Page page =new Page();

page.setPrevPage(pageUtil.getPrevPage());

page.setNextPage(pageUtil.getNextPage());

page.setShowUsers(list);

page.setShowPageNums(pageUtil.getShowPageNums());

page.setCurrentPage(pageUtil.getCurrentPage());

return page;

}

}

Service接口：

public interface IUserService {

public Page pageUsers(String currentPage) throws Exception;

}

Controller层：

public class UserController extends HttpServlet{

/**

*

*/

private static final long serialVersionUID = 1L;

private IUserService userService =new UserServiceImpl();

@Override

protected void doGet(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException {

String currentPage =req.getParameter("currentPage");

Page page =null;

try {

page =userService.pageUsers(currentPage);

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

req.setAttribute("page", page);

req.getRequestDispatcher("/page.jsp").forward(req, resp);

}

@Override

protected void doPost(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException {

super.doPost(req, resp);

}

}

导入jquery的js文件：



Page.jsp文件：

<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<!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=UTF-8">

<script type="text/javascript" src="js/jquery-2.1.3.js"></script>

<script type="text/javascript" src="js/jquery-2.1.3.min.js"></script>

<title>分页</title>

<style type="text/css">

a{

font-size:14px;

text-decoration:none;

}

td{

text-align:center;

}

#prevPage{

padding:6px;

color:blue;

width:24px;

height:24px;

border:1px solid #ccc;

}

#pageNum{

padding-top:6px;

padding-left:12px;

color:blue;

border:1px solid #ccc;

padding-right:12px;

padding-bottom:6px;

}

#nextPage{

padding:6px;

color:blue;

width:24px;

height:24px;

border:1px solid #ccc;

}

</style>

</head>

<body>

<div class="container" id="pagenation" align="center">

<table border="1" width="80%" cellpadding="5" cellspacing="0">

<tr>

<th>序号</th>

<th>用户名</th>

<th>性别</th>

</tr>

<c:forEach items="${page.showUsers}" var="user">

<tr>

<td>${user.id}</td>

<td>${user.username}</td>

<td>${user.gender}</td>

</tr>

</c:forEach>

</table>

</div>

<div>

<c:when test="${page.currentPage==1}">

<上一页

</c:when>

<c:otherwise>

<a href="http://localhost:8080/paging/user.htm?currentPage=${page.prevPage}" id="prevPage"><上一页</a>

</c:otherwise>

<c:forEach items="${page.showPageNums}" var="pageNum">

<a href="http://localhost:8080/paging/user.htm?currentPage=${pageNum}" id="pageNum">${pageNum}</a>

</c:forEach>

<a href="http://localhost:8080/paging/user.htm?currentPage=${page.nextPage}" id="nextPage">下一页></a>

</div>

</body>

<script type="text/javascript">

$(function(){

$("#prevPage").mousemove(function(){

$("#prevPage").css("border-color","#4a86e8");

$("#prevPage").css("background","#d5dce8");

});

$("#prevPage").mouseout(function(){

$("#prevPage").css("border-color","#ccc");

$("#prevPage").css("background","white");

});

$("#nextPage").mousemove(function(){

$("#nextPage").css("border-color","#4a86e8");

$("#nextPage").css("background","#d5dce8");

});

$("#nextPage").mouseout(function(){

$("#nextPage").css("border-color","#ccc");

$("#nextPage").css("background","white");

});

});

</script>

</html>

结果：