数据库配置文件.db(放在resource下)：

Mb.driver = com.mysql.cj.jdbc.Driver
Mb.url = jdbc:mysql://127.0.0.1:3306/数据库名
Mb.username = root
Mb.password = 密码

mybatis-config的xml文件（放在resource下）：

<?xml version="1.0" encoding="UTF-8" ?>
<!--mybatis约束-->
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><!--    连接数据库环境--><properties resource="数据库配置文件路径"></properties>
<!--    驼峰映射开启--><settings><setting name="mapUnderscoureToCamelCase" value="true"/></settings><!--    设置别名，以类名为别--><typeAliases><package name=""/></typeAliases><environments default="mybatis"><environment id="mybatis"><transactionManager type="JDBC"></transactionManager><dataSource type="POOLED"><property name="driver" value="${Mb.driver}"/><property name="url" value="${Mb.url}"/><property name="username" value="${Mb.username}"/><property name="password" value="${Mb.password}"/></dataSource></environment></environments><!--    引入映射文件--><mappers><mapper resource="mapper路径"></mapper></mappers>
</configuration>

Mapper：

<?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.dt.dao.UserMapper"><!--    <insert id="">-->
<!--     -->
<!--    </insert>--><!--    <update id="">-->
<!--    -->
<!--    </update>--><!--    <delete id="">-->
<!--      -->
<!--    </delete>--><!--  resultType 返回值类型--><select id="mapper里的函数名" resultType="实体类（全路径名）">sql搜索语句语句</select>
</mapper>

创建Mapper：

public interface XxxMapper {类型 xxx();
}

使用：

String resource = "mybaits-config.xml";//加载配置文件InputStream inputStream = Resources.getResourceAsStream(resource);SqlSessionFactory sqlSessionFactory  = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession=  sqlSessionFactory.openSession();XxxrMapper xxMapper = sqlSession.getMapper(XxxMapper（接口）.class);xxMapper.接口里面的方法();