VIPJAVA/02_JavaWeb/day08_mybatis/target/classes/com/lc/mapper/UserMapper.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.lc.mapper.UserMapper">
    <!--
        一对一  级联映射  属性

        需求 用户信息 + 部门信息
     -->
    <resultMap id="userByIdResultMap" type="com.lc.pojo.User">
        <id property="id" column="id" ></id>
        <result property="username" column="username" ></result>
        <result property="password" column="password" ></result>
        <result property="adderss" column="adderss" ></result>
        <result property="gender" column="gender" ></result>
        <result property="deptId" column="dept_id" ></result>

        <!-- 部门信息  列对应  -->
        <result property="dept.id" column="dept_id" ></result>
        <result property="dept.name" column="name" ></result>
        <result property="dept.comment" column="comment" ></result>


    </resultMap>

    <select id="getUserById" resultMap="userByIdResultMap" >
        SELECT
            *
        FROM
            t_user u INNER JOIN t_dept d ON u.dept_id = d.id
        WHERE
            u.id = #{id}
    </select>

    <!-- Association  -->
    <resultMap id="userByIdResultMapAssociation" type="com.lc.pojo.User">
        <id property="id" column="id" ></id>
        <result property="username" column="username" ></result>
        <result property="password" column="password" ></result>
        <result property="adderss" column="adderss" ></result>
        <result property="gender" column="gender" ></result>
        <result property="deptId" column="dept_id" ></result>

        <!-- association 一对一
            property 实体属性
            javaType 类型
         -->
        <association property="dept" javaType="com.lc.pojo.Dept" >
            <id property="id" column="id"></id>
            <result property="name" column="name" ></result>
            <result property="comment" column="comment" ></result>
        </association>

    </resultMap>

    <select id="getUserByIdAssociation" resultMap="userByIdResultMapAssociation" >
        SELECT
            *
        FROM
            t_user u INNER JOIN t_dept d ON u.dept_id = d.id
        WHERE
            u.id = #{id}
    </select>


    <resultMap id="userByIdStep" type="user">
        <id property="id" column="id" ></id>
        <result property="username" column="username" ></result>
        <result property="password" column="password" ></result>
        <result property="adderss" column="adderss" ></result>
        <result property="gender" column="gender" ></result>
        <result property="deptId" column="dept_id" ></result>

        <!--
            分布查询
            select
          -->
        <association
            property="dept"
            javaType="dept"
            select="com.lc.mapper.DeptMapper.getDeptByIdStep"
            column="dept_id"
        >

        </association>
    </resultMap>
    <!--
        分布查询
        getUserByIdStep  -->
    <select id="getUserByIdStep" resultMap="userByIdStep">
        select * from t_user where id = #{id}
    </select>



    <!-- 多的一方 -->
    <select id="getUserByIdStepCollection" resultType="user">
        select * from t_user where dept_id = #{id}
    </select>

</mapper>