通過MyBatis查找一張表的數據，某些字段的值爲空

上代碼：

<?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.gxuwz.assistant.mapper.UserMapper">

    <resultMap id="SysUserResultMap" type="com.gxuwz.assistant.entity.SysUser">
        <result column="user_id" property="userId" />
        <result column="user_name" property="userName" />
        <result column="passWord" property="passWord" />
        <result column="major" property="major" />
        <result column="institute" property="institute" />
        <result column="classes" property="classes" />
        <result column="grade" property="grade" />
        <result column="telephone" property="telephone" />
        <result column="email" property="email" />
        <result column="image_id" property="imageId" />
        <result column="lab_id" property="labId" />
    </resultMap>

    <select id="findUserById" resultMap="SysUserResultMap" resultType="com.gxuwz.assistant.entity.SysUser">
        select * from sys_user where user_id = #{id}
    </select>

</mapper>

問題所在：

是因爲我少寫了resultMap="SysUserResultMap" 這段代碼