如何在springboot中使用PageHelper分页插件

文章目录

• ​​1. pom依赖​​
• ​​2. yml​​
• ​​3. 实体类​​
• ​​4. mapper映射文件​​
• ​​4. mapper接口​​
• ​​5. service接口​​
• ​​6. 实现类​​
• ​​7. controller​​
• ​​8. 浏览器验证​​

使用思路：
1.引入myabtis和pagehelper依赖
2.yml中配置mybatis扫描和实体类
3. 这2行代码
pageNum：当前第几页
pageNum：显示多少条数据
userList：数据库查询的数据数据列表
    PageHelper.startPage(pageNum, pageSize);
    PageInfo pageInfo = new PageInfo(userList);
    最后返回一个pageInfo 对象即可，pageInfo 这个对象中只有数据一些信息，但是，没有成功失败的状态或者提示语。
    真实企业中会封装一个返回对象，把pageInfo 放到对象中

1. pom依赖

<!--Myabtis依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.2</version>
        </dependency>
        <!--pagehelper依赖-->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.13</version>
        </dependency>
        <!--mysql依赖-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.20</version>
        </dependency>
        <!--数据源-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.21</version>
        </dependency>
        <!--提高效率lombok插件-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

2. yml

spring:
  application:
    name: springboot-vue
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/vue?characterEncoding=UTF-8&serverTimezone=GMT%2B8
    username: root
    password: root

server:
  port: 8989
  servlet:
    context-path: /vue

#mybatis配置信息
mybatis:
  configuration:
    map-underscore-to-camel-case: true
    #控制台日志配置 打印sql
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  mapper-locations: classpath:mappers/*.xml
  type-aliases-package: com.baizhi.entity

#数据库方言
pagehelper:
  helper-dialect: mysql

#控制台日志配置
logging:
  pattern:
    console: "[%thread] %-5level %logger{36} - %msg%n"

3. 实体类

package com.baizhi.entity;

import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
import lombok.experimental.Accessors;

import java.io.Serializable;

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
@Accessors(chain = true)
public class TUser implements Serializable {
    private static final long serialVersionUID = 745741804375055500L;

    private Integer id;

    private String name;

    private Integer age;
    @JsonFormat(pattern = "yyyy-MM-dd", timezone = "GTM+8")
    private String bir;
}

4. mapper映射文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.baizhi.dao.TUserDao">

    <resultMap type="com.baizhi.entity.TUser" id="TUserMap">
        <result property="id" column="id" jdbcType="INTEGER"/>
        <result property="name" column="name" jdbcType="VARCHAR"/>
        <result property="age" column="age" jdbcType="INTEGER"/>
        <result property="bir" column="bir" jdbcType="VARCHAR"/>
    </resultMap>

    <select id="selectUserAll"  resultMap="TUserMap">
        select
         id, name, age, bir
        from vue.t_user
    </select>
</mapper>

4. mapper接口

package com.baizhi.dao;

import com.baizhi.entity.TUser;
import org.apache.ibatis.annotations.Mapper;
import java.util.List;

/**
 * (TUser)表数据库访问层
 *
 * @author makejava
 * @since 2020-05-05 18:39:21
 */
@Mapper
public interface TUserDao {

    List<TUser> selectUserAll();
}

5. service接口

package com.baizhi.service;

import com.baizhi.entity.TUser;
import com.github.pagehelper.PageInfo;

import java.util.List;

/**
 * (TUser)表服务接口
 *
 * @author makejava
 * @since 2020-05-05 18:39:22
 */
public interface TUserService {
    PageInfo list(Integer pageNum, Integer pageSize);
}

6. 实现类

package com.baizhi.service.impl;

import com.baizhi.dao.TUserDao;
import com.baizhi.entity.TUser;
import com.baizhi.service.TUserService;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

/**
 * (TUser)表服务实现类
 *
 * @author makejava
 * @since 2020-05-05 18:39:22
 */
@Service("tUserService")
public class TUserServiceImpl implements TUserService {
    @Resource
    private TUserDao tUserDao;

    public PageInfo list(Integer pageNum, Integer pageSize) {

        PageHelper.startPage(pageNum, pageSize);
        List<TUser> userList = this.tUserDao.selectUserAll();
        //如果返回前的数据 和 数据库实体 对象数据一致 采下面方式
        //如果不一致，采用 PageInfo pageInfo = new PageInfo(); pageInfo.setList(shippingList);
        PageInfo pageInfo = new PageInfo(userList);
        return pageInfo;
    }
}

7. controller

package com.baizhi.controller;

import com.baizhi.service.TUserService;
import com.github.pagehelper.PageInfo;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;

/**
 * (TUser)表控制层
 *
 * @author makejava
 * @since 2020-05-05 18:39:22
 */
@RestController
@CrossOrigin
@RequestMapping("user")
public class TUserController {
    /**
     * 服务对象
     */
    @Resource
    private TUserService tUserService;

    @GetMapping("findAll")
    public PageInfo findAll(@RequestParam(required = false, defaultValue = "1") Integer pageNum,
                            @RequestParam(required = false, defaultValue = "10") Integer pageSize) {
        PageInfo list = this.tUserService.list(pageNum, pageSize);
        return list;
    }
}

8. 浏览器验证

​​http://localhost:8989/vue/user/findAll?pageNum=0&pageSize=5​​