Spring Boot + MyBatis 如何借助PageHelper插件实现分页效果

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

        
        
            com.github.pagehelper
            pagehelper-spring-boot-starter
            1.2.5
        

yml配置

# PageHelper分页插件
pagehelper:
  helperDialect: mysql
  reasonable: true
  supportMethodsArguments: true
  params: 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 [email protected]
 * @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 [email protected]
 * @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 [email protected]
 * @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 [email protected]
 * @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 list(){
        List 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 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

   
   
   

   接口

5. 输入参数,调试接口

   
   
   

   返回数据

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

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