PageHelper实现了通用的分页查询，其支持的数据有，mysql、Oracle、DB2、PostgreSQL等主流的数据库。
使用说明：https://github.com/pagehelper/Mybatis-PageHelper/blob/master/wikis/en/HowToUse.md
导入依赖
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>5.1.4</version>
</dependency>mybatis-config.xml中配置
plugins在配置文件中的位置必须符合要求，否则会报错，顺序如下:
properties?, settings?, typeAliases?, typeHandlers?, objectFactory?,objectWrapperFactory?, plugins?, environments?, databaseIdProvider?, mappers?
<plugins>
<plugin interceptor="com.github.pagehelper.PageInterceptor" />
</plugins>接口
Long getTotalRowCount(String keywords);
Page<User> getUsersByPage(int pageIndex, int pageSize);
Page<User> getUsersByPage(String keywords, int pageIndex, int pageSize);
PageInfo<User> getUsersByPage2(int pageIndex, int pageSize);
PageInfo<User> getUsersByPage2(String keywords, int pageIndex, int pageSize);xml
<select id="getTotalRowCount" resultType="java.lang.Long">
select count(*) count
from t_user
where 1 = 1
<if test="keywords != null and keywords != ''">
and UserName like concat('%',#{keywords},'%')
</if>
</select>
<select id="getUsersByPage" resultType="User">
select Id,
UserName,
Password
from t_user
where 1 = 1
<if test="keywords != null and keywords != ''">
and UserName like concat('%',#{keywords},'%')
</if>
limit #{startIndex},#{pageSize}
</select>
<select id="getUsersByPage2" resultType="User">
select Id,
UserName,
Password
from t_user
where 1 = 1
<if test="keywords != null and keywords != ''">
and UserName like concat('%',#{keywords},'%')
</if>
</select>实体类
package com.etc.entity;
import java.util.List;
public class Page<T> {
/**
* 每页条数
*/
private int pageSize = 10;
/**
* 第几页
*/
private int pageIndex = 1;
/**
* 总的记录数
*/
private long totalRowCount;
/**
* 数据
*/
private List<T> data;
/**
* 是否有上一页
*/
private boolean hasPrevPage;
/**
* 是否有下一页
*/
private boolean hasNextPage;
/**
* @return the pageSize
*/
public int getPageSize() {
return pageSize;
}
/**
* @param pageSize the pageSize to set
*/
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
/**
* @return the pageIndex
*/
public int getPageIndex() {
return pageIndex;
}
/**
* @param pageIndex the pageIndex to set
*/
public void setPageIndex(int pageIndex) {
this.pageIndex = pageIndex;
}
/**
* @return the totalRowCount
*/
public long getTotalRowCount() {
return totalRowCount;
}
/**
* @param totalRowCount the totalRowCount to set
*/
public void setTotalRowCount(long totalRowCount) {
this.totalRowCount = totalRowCount;
}
/**
* @return the data
*/
public List<T> getData() {
return data;
}
/**
* @param data the data to set
*/
public void setData(List<T> data) {
this.data = data;
}
/**
* @return the totalPageCount
*/
public long getTotalPageCount() {
if(this.totalRowCount % this.pageSize == 0){
return this.totalRowCount / this.pageSize;
}else{
return this.totalRowCount / this.pageSize + 1;
}
}
/**
* @return the hasPrevPage
*/
public boolean getHasPrevPage() {
//什么情况下有上一页，如果当前页>1
return this.pageIndex > 1;
}
/**
* @return the hasNextPage
*/
public boolean getHasNextPage() {
//如果当前页和总的页数一样，则没有下一页，其它情况都有下一页
return this.pageIndex == this.getTotalPageCount() ? false : true;
}
public Page(){
}
/**
* 有参构造方法
* @param pageSize 每页的条数
* @param pageIndex 当前页码
* @param totalRowCount 总的记录数
* @param data 数据
*/
public Page(int pageSize, int pageIndex, long totalRowCount, List<T> data) {
super();
this.pageSize = pageSize;
this.pageIndex = pageIndex;
this.totalRowCount = totalRowCount;
this.data = data;
}
}
servie实现类
@Override
public Long getTotalRowCount(String keywords){
return userDao.getTotalRowCount(keywords);
}
@Override
public Page<User> getUsersByPage(int pageIndex, int pageSize){
int startIndex = (pageIndex - 1) * pageSize;
List<User> users = userDao.getUsersByPage(null,startIndex,pageSize);
Long totalRowCount = userDao.getTotalRowCount(null);
com.etc.entity.Page<User> page = new com.etc.entity.Page<User>(pageIndex,pageSize,totalRowCount,users);
return page;
}
@Override
public Page<User> getUsersByPage(String keywords, int pageIndex, int pageSize){
int startIndex = (pageIndex - 1) * pageSize;
List<User> users = userDao.getUsersByPage(keywords,startIndex,pageSize);
Long totalRowCount = userDao.getTotalRowCount(keywords);
com.etc.entity.Page<User> page = new com.etc.entity.Page<User>(pageIndex,pageSize,totalRowCount,users);
return page;
}
@Override
public PageInfo<User> getUsersByPage2(int pageIndex, int pageSize){
PageHelper.startPage(pageIndex,pageSize,true);
List<User> users = userDao.getUsersByPage2(null);
PageInfo<User> pageInfo = new PageInfo<>(users);
return pageInfo;
}
@Override
public PageInfo<User> getUsersByPage2(String keywords, int pageIndex, int pageSize){
PageHelper.startPage(pageIndex,pageSize,true);
List<User> users = userDao.getUsersByPage2(keywords);
PageInfo<User> pageInfo = new PageInfo<>(users);
return pageInfo;
}测试类
@Test
/**
* 自定义分页类，没有传递关键词参数
*/
public void testGetUsersByPageWithoutKeywords(){
com.etc.entity.Page<User> page = userService.getUsersByPage(3,2);
System.out.println(page);
}
@Test
/**
* 自定义分页类，有传递关键词参数
*/
public void testGetUsersByPageWithKeywords(){
com.etc.entity.Page<User> page = userService.getUsersByPage("e",2,1);
System.out.println(page);
}
@Test
/**
* 使用分页插件，没有传递关键词参数
*/
public void testGetUsersByPage2WithoutKeywords(){
com.github.pagehelper.PageInfo<User> page = userService.getUsersByPage2(3,2);
System.out.println(page);
}
@Test
/**
* 使用分页插件，传递关键词参数
*/
public void testGetUsersByPage2WithKeywords(){
com.github.pagehelper.PageInfo<User> page = userService.getUsersByPage2("e",2,1);
System.out.println(page);
}
}自定义分页查询jsp页面
当前是第${page.pageIndex}页,共${page.totalPageCount }页，总记录数为${page.totalRowCount }条。
<hr>
<form action="UserServlet?op=getusersbypage" method="post" id="pageForm">
<input type="hidden" name="pageIndex" id="pageIndex" />
<button onclick="javascript:findPage(1)">首页</button>
<c:if test="${page.hasPrevPage }">
<button onclick="javascript:findPage(${page.pageIndex-1})">上一页</button>
</c:if>
<c:forEach begin="1" end="${page.totalPageCount }" step="1" var="index">
<button onclick="javascript:findPage(${index})">${index }</button>
</c:forEach>
<c:if test="${page.hasNextPage }">
<button onclick="javascript:findPage(${page.pageIndex+1})">下一页</button>
</c:if>
<button onclick="javascript:findPage(${page.totalPageCount})">尾页</button>
<input type="text" id="toPage" /> <button onclick="jump(${page.totalPageCount})">跳转</button>
</form>
<script>
function findPage(pageIndex){
var form = document.getElementById('pageForm');
var page = document.getElementById('pageIndex') ;
page.value = pageIndex;
form.submit();
}
function jump(totalPageCount){
var pageIndex = document.getElementById('toPage').value;
if(pageIndex < 1){
findPage(1);
}else if(pageIndex > totalPageCount){
findPage(totalPageCount);
}else{
findPage(pageIndex);
}
}分页插件页面
当前是第${page.pageNum}页,共${page.pages }页，总记录数为${page.total }条。
<hr>
<form action="UserServlet?op=getusersbypage" method="post" id="pageForm">
<input type="hidden" name="pageIndex" id="pageIndex" />
<button onclick="javascript:findPage(1)">首页</button>
<c:if test="${page.hasPreviousPage }">
<button onclick="javascript:findPage(${page.pageNum-1})">上一页</button>
</c:if>
<c:forEach begin="1" end="${page.pages }" step="1" var="index">
<button onclick="javascript:findPage(${index})">${index }</button>
</c:forEach>
<c:if test="${page.hasNextPage }">
<button onclick="javascript:findPage(${page.pageNum+1})">下一页</button>
</c:if>
<button onclick="javascript:findPage(${page.pages})">尾页</button>
<input type="text" id="toPage" /> <button onclick="jump(${page.pages})">跳转</button>
</form>
<script>
function findPage(pageIndex){
var form = document.getElementById('pageForm');
var page = document.getElementById('pageIndex') ;
page.value = pageIndex;
form.submit();
}
function jump(totalPageCount){
var pageIndex = document.getElementById('toPage').value;
if(pageIndex < 1){
findPage(1);
}else if(pageIndex > totalPageCount){
findPage(totalPageCount);
}else{
findPage(pageIndex);
}
}