入门程序大概步骤叙述：

步骤一：创建springboot工程并且数据库提前创建表

步骤二：创建springboot工程对Mybatis相关依赖注意打勾

步骤三：编写查找方法

步骤四：编写测试方法

项目目录结构与数据库以及代码：

项目目录结构

数据库db02与表user

User（实体类代码）

package com.itheima.pojo;public class User {private Integer id;private String name;private short age;private short gender;private String phone;public User() {}public User(Integer id, String name, short age, short gender, String phone) {this.id = id;this.name = name;this.age = age;this.gender = gender;this.phone = phone;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public short getAge() {return age;}public void setAge(short age) {this.age = age;}public short getGender() {return gender;}public void setGender(short gender) {this.gender = gender;}public String getPhone() {return phone;}public void setPhone(String phone) {this.phone = phone;}@Overridepublic String toString() {return "User{" +"id=" + id +", name='" + name + '\'' +", age=" + age +", gender=" + gender +", phone='" + phone + '\'' +'}';}
}

UserMapper（接口代码）

package com.itheima.mapper;import com.itheima.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;import java.util.List;@Mapper//在运行时,会自动生成该接口的实现类对象(代理对象)，并且将该对象交给IOC容器管理
public interface UserMapper {@Select("select * from user")public List<User> list();
}

application.properties（数据库配置代码）

#驱动类名称
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#数据库连接的url
spring.datasource.url=jdbc:mysql://localhost:3306/db02
#连接数据库的用户名
spring.datasource.username=root
#连接数据库的密码
spring.datasource.password=root

SpringbootMybatisQuickstartApplicationTests（测试类代码）

package com.itheima;import com.itheima.mapper.UserMapper;
import com.itheima.pojo.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;import java.util.List;@SpringBootTest//springboot整合单元测试的注解
class SpringbootMybatisQuickstartApplicationTests {@Autowiredprivate UserMapper userMapper;@Testpublic void testListUser(){List<User> userList = userMapper.list();userList.stream().forEach(user -> {System.out.println(user);});}
}

结果