（官网文档:http://mybatis.github.io/mybatis-3/zh/sqlmap-xml.html#Result_Maps)

简单结果映射

• 列名与属性名匹配（会自动匹配,忽略大小写）官网文档http://mybatis.github.io/mybatis-3/zh/sqlmap-xml.html#Auto-mapping

  <select id="selectUsers" resultType="com.someapp.model.User">
    select id, username, hashedPassword
    from some_table
    where id = #{id}
  </select>
  

• 列名与属性名不匹配（手动匹配）

   <resultMap id="userResultMap" type="User">
    <id property="id" column="user_id" />
    <result property="username" column="user_name"/>
    <result property="password" column="hashed_password"/>
  </resultMap>
  

或

<select id="selectUsers" resultType="User">
  select
    user_id             as "id",
    user_name           as "userName",
    hashed_password     as "hashedPassword"
  from some_table
  where id = #{id}
</select>

复杂结果映射

官方例子:一个博客对应一个作者，一个博客对应多篇文章

• 含有复合类型(自定义类型)

  <resultMap id="blogResult" type="Blog">
    <id property="id" column="blog_id" />
    <result property="title" column="blog_title"/>
    <!-- 对应一个作者 ,使用javaType指定类型-->
    <association property="author" javaType="Author">
      <id property="id" column="author_id"/>
      <result property="username" column="author_username"/>
      <result property="password" column="author_password"/>
      <result property="email" column="author_email"/>
      <result property="bio" column="author_bio"/>
    </association>
  </resultMap>
  

可以复用

<resultMap id="blogResult" type="Blog">
  <id property="id" column="blog_id" />
  <result property="title" column="blog_title"/>
  <!-- 需要使用resultMap指定结果映射 -->
  <association property="author" column="blog_author_id" javaType="Author" resultMap="authorResult"/>



</resultMap>

<resultMap id="authorResult" type="Author">
  <id property="id" column="author_id"/>
  <result property="username" column="author_username"/>
  <result property="password" column="author_password"/>
  <result property="email" column="author_email"/>
  <result property="bio" column="author_bio"/>
</resultMap>

• 含有集合(collection)

  <resultMap id="blogResult" type="Blog">
    <id property="id" column="blog_id" />
    <result property="title" column="blog_title"/>
    <!-- 对应多篇文章，使用ofType指定类型 -->
    <collection property="posts" ofType="Post">
      <id property="id" column="post_id"/>
      <result property="subject" column="post_subject"/>
      <result property="body" column="post_body"/>
    </collection>
  </resultMap>
  

可以复用

<resultMap id="blogResult" type="Blog">
  <id property="id" column="blog_id" />
  <result property="title" column="blog_title"/>
  <!-- 需要使用resultMap指定结果映射 -->
  <collection property="posts" ofType="Post" resultMap="blogPostResult" columnPrefix="post_"/>
</resultMap>

<resultMap id="blogPostResult" type="Post">
  <id property="id" column="id"/>
  <result property="subject" column="subject"/>
  <result property="body" column="body"/>
</resultMap>