src/main/resources/mapper/FavoriteMapper.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.example.myproject.mapper.FavoriteMapper">
    <select id="selectByUserId" resultType="com.example.myproject.entity.FavoriteEntity"> SELECT * FROM favorite WHERE user_id = #{userId} </select>
</mapper>