一、准备工作

详情参考：https://blog.csdn.net/hznb_369/article/details/121039732.
不想引入jar或者找不到jar包可以在pom.xml添加依赖

<!--数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.22</version>
        </dependency>

        <!--mybatis3-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7</version>
        </dependency>

二、实体类的创建

在这里插入图片描述

Employee

import lombok.Data;

@Data
public class Employee {
    private Integer id;
    private String lastName;
    private String gender;
    private String email;

    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", lastName='" + lastName + '\'' +
                ", gender='" + gender + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

EmployeeMapper

public interface EmployeeMapper {

    public Employee getEmpById(Integer id);
}

需要映射的配置文件EmployeeMapper.xml

<?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.znb.mapper.EmployeeMapper">

    <!--根据id进行查询-->
    <select id="getEmpById" resultType="employee" databaseId="mysql">
        select * from tbl_employee where id = #{id}
    </select>

</mapper>

三、测试

public class MybatisTest {

    InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
    // 获取实例对象
    SqlSession sqlSession = sqlSessionFactory.openSession();

    public MybatisTest() throws IOException {
    }
    @Test
    public void test1(){
        try {
            EmployeeMapper mapper = sqlSession.getMapper(EmployeeMapper.class);
            Employee empById = mapper.getEmpById(1);
            System.out.println(empById);
        }finally {
            sqlSession.close();
        }
    }
}