创建项目

第一步（完成以下操作进行下一步）：

第二步：         

一、 原理概述

PageHelper是MyBatis的一个插件，内部实现了一个PageInterceptor拦截器。Mybatis会加载这个拦截器到拦截器链中。在我们使用过程中先使用PageHelper.startPage这样的语句在当前线程上下文中设置一个ThreadLocal变量，再利用PageInterceptor这个分页拦截器拦截，从ThreadLocal中拿到分页的信息，如果有分页信息拼装分页SQL（limit语句等）进行分页查询，最后再把ThreadLocal中的东西清除掉。

二、 springboot+pageHelper带条件分页

2.1 添加依赖

    com.github.pagehelper    pagehelper-spring-boot-starter    1.4.1

2.2 pageHelper分页插件的yml配置

#pageHelper 分页插件的配置 pagehelper:   auto-dialect: true   reasonable: true   support-methods-arguments: true   params: count=countSql

2.3 建立实体类

package com.boot.springboot1223.pojo;​​import com.baomidou.mybatisplus.annotation.IdType;import com.baomidou.mybatisplus.annotation.TableField;import com.baomidou.mybatisplus.annotation.TableId;import com.baomidou.mybatisplus.annotation.TableName;import lombok.Data;​import java.io.Serializable;​import java.util.Date;​@Data@TableName("action")public class Action{​        @TableId(type = IdType.AUTO)    private Integer actionId;        private String orderSn;        private Integer actionUser;        private Integer orderStatus;        private Integer payStatus;        private Integer shippingStatus;        private String actionNote;        private String actionTime;        private String statusDesc;        @TableField(exist = false)    private String orderTime;​​}

2.4 mapper层 (数据持久层)

package com.boot.springboot1223.mapper;​import com.baomidou.mybatisplus.core.mapper.BaseMapper;import com.boot.springboot1223.pojo.Action;import org.apache.ibatis.annotations.Mapper;​import java.util.List;@Mapperpublic interface ActionMapper extends BaseMapper {​        List findPage(Action action);​}

2.5 service层 (业务逻辑层)

package com.boot.springboot1223.service;​import com.baomidou.mybatisplus.extension.service.IService;import com.boot.springboot1223.pojo.Action;import com.github.pagehelper.PageInfo;​import java.util.List;​public interface ActionService extends IService {    PageInfo findPage(Action action,Integer pageIndex,Integer pageSize);}

package com.boot.springboot1223.service.impl;​import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;import com.boot.springboot1223.mapper.ActionMapper;import com.boot.springboot1223.pojo.Action;import com.boot.springboot1223.service.ActionService;import com.github.pagehelper.PageHelper;import com.github.pagehelper.PageInfo;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;​import java.util.List;​@Servicepublic class ActionServiceImpl extends ServiceImpl implements ActionService {    @Autowired    private ActionMapper actionMapper;​    @Override    public PageInfo findPage(Action action, Integer pageIndex, Integer pageSize) {        //调用分页插件的工具类  计算总页数        PageHelper.startPage(pageIndex,pageSize);        //获取所有数据        List page = actionMapper.findPage(action);        //获取所有的数据直接给pageInfo        PageInfo pageInfo=new PageInfo(page);        return pageInfo;    }}

2.6 controller层

package com.boot.springboot1223.controller;​import com.boot.springboot1223.pojo.Action;import com.boot.springboot1223.pojo.Order;import com.boot.springboot1223.service.ActionService;import com.boot.springboot1223.service.OrderService;import com.github.pagehelper.PageInfo;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;​@Controllerpublic class ActionController {    @Autowired    private ActionService actionService;​    @RequestMapping("/findPage")    public String findPage(            Action action,            @RequestParam(value = "pageIndex",defaultValue = "1") Integer pageIndex,            @RequestParam(value = "pageSize",defaultValue = "1",required = false) Integer pageSize,            Model model    ){        PageInfo page = actionService.findPage(action,pageIndex, pageSize);        model.addAttribute("path","findPage?pageIndex=");        model.addAttribute("page",page);        model.addAttribute("action",action);        return "list";    }}

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来源地址：https://blog.csdn.net/qq_57512436/article/details/128446865