mybatisplus分页和pagehelper(mybatisplus分页插件原理)

在com包下创建文件config.MybatisPlusConfig

package com.config;


import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.autoconfigure.ConfigurationCustomizer;
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;

@Configuration

public class MybatisPlusConfig {
    
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }

}

创建测试文件

package com.example.mybatisplus;


import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.mapper.UserMapper;
import com.example.pojo.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class MybatisPLusPluginsTest {
    @Autowired
    private UserMapper userMapper;

    @Test
    public void test(){
        //1页  3条数据
        Page page=new Page<>(1,3);
        Page userPage = userMapper.selectPage(page, null);
        System.out.println("总页数： "+userPage.getPages());
        System.out.println("所有数据显示： "+userPage.getRecords());
        System.out.println("总记录数： "+userPage.getTotal());
        userPage.getRecords().forEach(System.out::println);
    }
}

package com.example.mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.pojo.User;
import org.apache.ibatis.annotations.Param;
import org.springframework.stereotype.Repository;

import java.util.Map;

@Repository
public interface UserMapper extends baseMapper {

    //根据id查询用户信息为map集合
    //自定义
    Map selectMapById(Long id);

    //自定义分页功能
    //通过年龄查询用户信息并分页
    //Mybatis-PLus所提供的分页对象，必须位于第一个参数位置
    Page selectPageVo(@Param("page")Page page,@Param("age") Integer age);
}

spring:
  #配置数据源的信息
  datasource:
    #配置数据源的类型
    type:
    #配置数据库的各个信息
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mybatis_plus?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8
    username: root
    password: '011012'
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  #配置Mybatis-plus的全局变量
  global-config:
    db-config:
      #来设置实体类对应表的统一前缀
      table-prefix: t_
      #设置统一的主键生成策略
      id-type: auto
      #配置类型别名所对应的包
      type-aliases-package: com/example/pojo

userMapper.xml

    
    
        select * from user where id=#{id}
    

    
    
    select * from user where age>#{age}
    

@Test
    public void test2(){
        Page page=new Page<>(1,3);
        userMapper.selectPageVo(page,20);
        System.out.println(page);
    }