一，环境工具准备

工具：IDEA，JDK8

二，创建springboot项目

三，修改pom.xml文件，添加mybatis-plus

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.2</version>
        </dependency>

完整的pom文件如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>mybatisplus20220303</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mybatisplus20220303</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.2</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

四，修改配置

application.properties文件重命名成application.yml?，配置文件如下，数据库是MySQL，需要创建库mybatisplus

server:
  port: 8088

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mybatisplus
    username: root
    password: 123456

?五，创建表并任意添加一条测试数据即可

CREATE TABLE `sys_user` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键ID',
  `name` varchar(255) DEFAULT NULL COMMENT '姓名',
  `id_card` varchar(255) DEFAULT NULL COMMENT '身份证号码',
  `mobile` varchar(255) DEFAULT NULL COMMENT '手机号码',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8mb4;

?六，编码

package com.example.mybatisplus20220303.entity;

import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;

/**
 * @author YunDuan-Clutch
 * @date 2022/3/3 9:35
 */
@Data
@TableName("sys_user")
public class SysUser {

    private Long id;
    private String name;
    private String idCard;
    private String mobile;

}

package com.example.mybatisplus20220303.dao;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.mybatisplus20220303.entity.SysUser;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface SysUserDao extends BaseMapper<SysUser> {
}

package com.example.mybatisplus20220303;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * 启动类
 */
@MapperScan("com.example.mybatisplus20220303.dao")
@SpringBootApplication
public class Mybatisplus20220303Application {

    public static void main(String[] args) {
        SpringApplication.run(Mybatisplus20220303Application.class, args);
    }

}

七，启动

八，测试编码

package com.example.mybatisplus20220303;

import com.example.mybatisplus20220303.dao.SysUserDao;
import com.example.mybatisplus20220303.entity.SysUser;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

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

@SpringBootTest
public class Mybatisplus20220303ApplicationTests {

    /**
     * 这里使用@Resource的原因是，使用@Autowired时报错：Could not autowire. No beans of 'SysUserDao' type found.
     */
    @Resource
    private SysUserDao sysUserDao;

    @Test
    void contextLoads() {
        System.out.println("========== 测试一下mybatis-plus功能 ==========");
        List<SysUser> listSysUser = sysUserDao.selectList(null);
        System.out.println("长度是：" + listSysUser.size());
        listSysUser.forEach(user -> {
            System.out.println(user.toString());
        });
    }

}