mybatis中的resultMap

<?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">

<!-- namespace的名字需要跟接口的类名一致 -->
<mapper namespace="cn.bdqn.dao.UserMapper">
    <!-- 当数据库中的字段信息与对象的属性不一致时需要通过resultMap来映射 -->
    <resultMap type="User" id="seachUserResult">
        <result property="id" column="id"/>
        <result property="userCode" column="userCode"/>
        <result property="userName" column="userName"/>
        <result property="roleId" column="roleId"/>
        <result property="roleName" column="roleName"/>
    </resultMap>
    
    
    <select id="count" resultType="int">
        select count(1) from user
    </select>
    
    <insert id="add" parameterType="User">
        insert into user (userCode,userName,userPassword) 
            values (#{userCode},#{userName},#{userPassword})
    </insert>
    
    <update id="update" parameterType="User">
        update user set userCode=#{userCode},userName=#{userName},
            userPassword=#{userPassword} where id=#{id}
    </update>
    
    <delete id="delete" parameterType="User">
        delete from user where id=#{id}
    </delete>
    
    <select id="getUserList" resultType="User">
        select * from user
    </select>
    
    <select id="getUserListByRoleId" parameterType="Role" resultMap="seachUserResult">
        select u.*,r.roleName as roleName from user u,role r where u.roleId = r.id and u.roleId = #{id}
    </select>
    
</mapper>