概述

上文中已经介绍了Spring和MyBatis的整合,在上文的基础上我们加入了PageHelper这个插件，来实现MyBatis列表查询的分页效果

PageHelper是啥
PageHelper是一个强大实用的 MyBatis 分页插件，可以帮助我们快速的实现MyBatis分页功能,对MyBatis毫无侵入，只是对MyBatis的执行进行了拦截来实现分页效果。

**PageHelper 开源仓库 *
https://github.com/pagehelper/Mybatis-PageHelper

开始使用PageHelper

1.在pom.xml文件中加入PageHelper依赖,并在yml配置文件中加入分页配置

        <dependency><groupId>com.github.pagehelpergroupId><artifactId>pagehelper-spring-boot-starterartifactId><version>1.2.5version>dependency>

yml配置

# PageHelper分页插件pagehelper:  helperDialect: mysql  reasonable: true  supportMethodsArguments: trueparams: count=countSql

2. 创建工具包com.zhlab.demo.utils、com.zhlab.demo.utils.page,并创建相关类

• 页请求参数类:PageRequest.java

• 分页结果返回类:PageResult.java

• 分页工具类:PageUtil.java

/************************PageRequest.java************************/package com.zhlab.demo.utils.page;

/** * @ClassName PageRequest * @Description //分页请求参数类 * @Author singleZhang * @Email 405780096@qq.com * @Date 2020/10/31 0031 上午 11:00 **/public class PageRequest {

/**     * 当前页码     */private int pageNum;/**     * 每页数量     */private int pageSize;

public int getPageNum() {return pageNum;}public void setPageNum(int pageNum) {this.pageNum = pageNum;}public int getPageSize() {return pageSize;}public void setPageSize(int pageSize) {this.pageSize = pageSize;}

}

/************************PageResult.java************************/package com.zhlab.demo.utils.page;

import java.util.List;

/** * @ClassName PageResult * @Description //分页结果返回类 * @Author singleZhang * @Email 405780096@qq.com * @Date 2020/10/31 0031 上午 11:00 **/public class PageResult {

/**     * 当前页码     */private int pageNum;/**     * 每页数量     */private int pageSize;/**     * 记录总数     */private long totalSize;/**     * 页码总数     */private int totalPages;/**     * 返回的各类数据模型     */private List<?> content;public int getPageNum() {return pageNum;}public void setPageNum(int pageNum) {this.pageNum = pageNum;}public int getPageSize() {return pageSize;}public void setPageSize(int pageSize) {this.pageSize = pageSize;}public long getTotalSize() {return totalSize;}public void setTotalSize(long totalSize) {this.totalSize = totalSize;}public int getTotalPages() {return totalPages;}public void setTotalPages(int totalPages) {this.totalPages = totalPages;}public List<?> getContent() {return content;}public void setContent(List<?> content) {this.content = content;}

}

/************************PageUtil.java************************/package com.zhlab.demo.utils;

import com.github.pagehelper.PageInfo;import com.zhlab.demo.utils.page.PageResult;

/** * @ClassName PageUtil * @Description //分页工具类 * @Author singleZhang * @Email 405780096@qq.com * @Date 2020/10/31 0031 上午 11:03 **/public class PageUtil {

/**     * 将分页信息封装到统一的接口     * @param pageInfo     * @return     */public static PageResult getPageResult(PageInfo<?> pageInfo) {PageResult pageResult = new PageResult();        pageResult.setPageNum(pageInfo.getPageNum());        pageResult.setPageSize(pageInfo.getPageSize());        pageResult.setTotalSize(pageInfo.getTotal());        pageResult.setTotalPages(pageInfo.getPages());        pageResult.setContent(pageInfo.getList());return pageResult;}}

3. 在接口层UserController.java中新增分页测试方法findPage(PageRequest pageRequest)

package com.zhlab.demo.controller;

import com.github.pagehelper.PageHelper;import com.github.pagehelper.PageInfo;import com.zhlab.demo.model.SysAdminUser;import com.zhlab.demo.service.SysAdminUserService;import com.zhlab.demo.utils.PageUtil;import com.zhlab.demo.utils.page.PageRequest;import com.zhlab.demo.utils.page.PageResult;import io.swagger.annotations.ApiOperation;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.*;

import java.util.List;

/** * @ClassName UserController * @Description //用户接口层 * @Author singleZhang * @Email 405780096@qq.com * @Date 2020/10/31 0031 上午 9:43 **/@RestController@RequestMapping("/user")public class UserController {

@Autowired    SysAdminUserService sysAdminUserService;

/* 方法注解 */@ApiOperation(value = "方法名:用户列表", notes = "获取用户列表")@GetMapping("/list")public List<SysAdminUser> list(){        List<SysAdminUser> list = sysAdminUserService.findAll();

return list;}

@ApiOperation(value = "方法名:用户列表分页", notes = "获取分页用户列表")@PostMapping(value="/findPage")public PageResult findPage(@RequestBody PageRequest pageRequest) {

startPage(pageRequest); //开启分页,pageHelp会自动拦截mybatis的sql        List<SysAdminUser> list = sysAdminUserService.findAll();return PageUtil.getPageResult(new PageInfo<>(list));}

/**     * 启动分页     * */private void startPage(PageRequest pageRequest){        PageHelper.startPage(pageRequest.getPageNum() == 0?1:pageRequest.getPageNum(),                pageRequest.getPageSize()==0?5:pageRequest.getPageSize());}

}

4. 完事了?对！已经完事了,就这么简单,来看看执行效果吧

5. 输入参数,调试接口

总结

PageHelper的整合还是比较简单的,如果想更深入的了解,它还可以玩出花来,以后慢慢研究,加油打工人!

项目地址

https://gitee.com/kaixinshow/springboot-note