一、后台分页配置

MyBatis Plus自带分页插件（即BaseMapper接口中的selectPage()方法），只要简单的配置即可实现分页功能，具体步骤如下：

1. 配置分页插件

新创一个配置类，在配置类里面配置分页插件

package com.gblfy.flowable.config;import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;/*** MyBatisPlus 分页插件配置** @Author gblfy* @Date 2022-05-04 14:41**/
@Configuration
public class MyBatisPlusPaginationInnerConfig {/*** 分页插件（官网最新）*/@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));return interceptor;}}

2. 编写分页代码

分页的所有数据都在userPage对象中封装着，所以可以调用userPage对象的一系列方法对分页数据进行操作。

  package com.gblfy.flowable.service.impl;import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.gblfy.flowable.entity.SysUser;
import com.gblfy.flowable.mapper.SysUserMapper;
import com.gblfy.flowable.service.SysUserService;
import com.gblfy.flowable.tools.pager.PagerModel;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;/*** <p>* 用户信息表 服务实现类* </p>** @author gblfy* @since 2022-05-04*/
@Slf4j
@Service
public class SysUserServiceImpl implements SysUserService {@Autowiredprivate SysUserMapper userMapper;@Overridepublic PagerModel<SysUser> list(Page<SysUser> page, QueryWrapper<SysUser> queryWrapper) {Page<SysUser> userIPage = userMapper.selectPage(page, queryWrapper);// 分页的所有数据都在userPage对象中封装着// 获取总页数long pages = userIPage.getPages();//一页显示几条数据long size = userIPage.getSize();// 获取当前页long current = userIPage.getCurrent();// 获取当前页数据集合List<SysUser> records = userIPage.getRecords();// 获取总记录数long total = userIPage.getTotal();// 当前页是否有下一页boolean hasNext = userIPage.hasNext();// 当前页是否有上一页boolean hasPrevious = userIPage.hasPrevious();System.out.println("总页数pages=" + pages);System.out.println("当前页current=" + current);System.out.println("当前页显示几条数据size=" + size);System.out.println("当前页数据集合records=" + records);System.out.println("总记录数total=" + total);System.out.println("是否有下一页hasNext=" + hasNext);System.out.println("是否有上一页hasPrevious=" + hasPrevious);return new PagerModel<>(userIPage.getTotal(), records);}@Overridepublic Page<SysUser> listPage(Page<SysUser> page, QueryWrapper<SysUser> queryWrapper) {return userMapper.selectPage(page, queryWrapper);}
}

3. 测试

当前数据库的user表中有14条记录，设置当前页数为1，每页记录数为10。
如图：

controller

package com.gblfy.flowable.controller;import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.gblfy.flowable.entity.SysUser;
import com.gblfy.flowable.service.SysUserService;
import com.gblfy.flowable.tools.pager.PagerModel;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;/*** MyBatisPlus 分页测试** @Author gblfy* @Date 2022-05-04 15:32**/
@RestController
@RequestMapping("/page")
public class MyBatisPlusPaginateController {@Autowiredprivate SysUserService userService;@GetMapping("/list")public PagerModel<SysUser> list(@RequestParam(value = "keyword", defaultValue = "") String keyword,@RequestParam(value = "pageNum", defaultValue = "1") Integer pageNum,@RequestParam(value = "pageSize", defaultValue = "5") Integer pageSize) {QueryWrapper<SysUser> queryWrapper = new QueryWrapper<>();//条件构造器queryWrapper.like("user_name", keyword);//模糊查询LikePage<SysUser> page = new Page(pageNum, pageSize);//分页插件return userService.list(page, queryWrapper);//查询数据}@GetMapping("/listPage")public Page<SysUser> listPage(@RequestParam(value = "keyword", defaultValue = "") String keyword,@RequestParam(value = "pageNum", defaultValue = "1") Integer pageNum,@RequestParam(value = "pageSize", defaultValue = "5") Integer pageSize) {QueryWrapper<SysUser> queryWrapper = new QueryWrapper<>();//条件构造器queryWrapper.like("user_name", keyword);//模糊查询LikePage<SysUser> page = new Page(pageNum, pageSize);//分页插件return userService.listPage(page, queryWrapper);//查询数据}
}

默认返回Page基本可以满足，如果自定义返回封装，参考以下案例即可

package com.gblfy.flowable.tools.pager;import lombok.Builder;
import lombok.Data;import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;/*** 分页** @author gblfy* @date 2022-05-03**/
@Data
@Builder(toBuilder = true)
public class PagerModel<T> implements Serializable {private static final long serialVersionUID = 4804053559968742915L;/*** 总记录数*/private long total;/*** 每页的查询结果集*/private List<T> rows = new ArrayList();/*** 获取总页数*/private long pages;/*** 获取当前页*/private long current;/*** 当前页显示几条数据*/private long size;/*** 当前页是否有下一页*/private boolean hasNext;/*** 当前页是否有上一页*/private boolean hasPrevious;public PagerModel() {}public PagerModel(long total, List<T> rows) {this.total = total;this.rows = rows;}public PagerModel(long total, List<T> rows, long pages, long current) {this.total = total;this.rows = rows;this.pages = pages;this.current = current;}public PagerModel(long total, List<T> rows, long pages, long current, long size) {this.total = total;this.rows = rows;this.pages = pages;this.current = current;this.size = size;}public PagerModel(long total, List<T> rows, long pages, long current, boolean hasNext, boolean hasPrevious) {this.total = total;this.rows = rows;this.pages = pages;this.current = current;this.hasNext = hasNext;this.hasPrevious = hasPrevious;}public PagerModel(long total, List<T> rows, long pages, long current, long size, boolean hasNext, boolean hasPrevious) {this.total = total;this.rows = rows;this.pages = pages;this.current = current;this.size = size;this.hasNext = hasNext;this.hasPrevious = hasPrevious;}
}

二、自定义查询

2.1. 自定义接口

如果想自定义查询那么在UserMapper.java里面写个方法

 Page<User> selectPageVo(@Param("page") Page<User> page,@Param("age") Integer age);

2.2. 自定义查询

UserMapper.xml文件的查询语句

<select id="selectPageVo" resultType="com.mybatis_plus.bean.User">SELECT id,name,age,email FROM user WHERE age>#{age}
</select>

2.3. 测试自定义分页

@Testvoid test02(){//测试自定义分页Page<User> page=new Page<>(1,3);userMapper.selectPageVo(page,20);//调用自定义的查询System.out.println(page.getRecords());//获取当前页数据 3条记录System.out.println(page.getSize());//获取每页的条数 3System.out.println(page.getCurrent()); //获取当前页码 1System.out.println(page.getPages());//获取总页数 2System.out.println(page.getTotal());//获取总记录数 4System.out.println(page.hasNext());//获取有没有下一页 trueSystem.out.println(page.hasPrevious());//获取是否有上一页 false}