Mybatis 中的一对一,一对多,多对多的配置原则示例代码

什么是 mybatis ？

mybatis 是支持定制化 sql、存储过程以及高级映射的优秀的持久层框架。mybatis 避免了几乎所有的 jdbc 代码和手动设置参数以及获取结果集。mybatis 可以对配置和原生map使用简单的 xml 或注解，将接口和 java 的 pojos(plain old java objects,普通的 java对象)映射成数据库中的记录。

表：market_plan(营销计划(关联了用户))

market_plan_product(产品关联营销计划)
market_plan_label(标签关联营销计划)
market_plan_ideadata(创意素材关联营销计划)
user_ideadata_activity(活动关联用户，活动关联创意素材表)
user(用户表)

配置原则：a关联b，将a的resultmap关联(association)到b的resultmap中，这样才能在写关联查询sql语句的时候，查询出a,b表中的属性。多张表的关联也是一样的道理！

配置xml示例：

<resultmap id="userresultmap" type="com.mchuan.fastmarketplat.b.entity.user">
<id column="user_id" property="id" />
<result column="account" property="account" />
<result column="name" property="name" />
<result column="mobile" property="mobile" />
</resultmap>
<resultmap id="labelresultmap"
type="com.mchuan.fastmarketplat.b.entity.marketplanlabel">
<id property="id" column="label_id" />
<result property="gender" column="gender" />
<result property="area" column="area" />
<result property="age" column="age" />
<result property="devicetype" column="device_type" />
<result property="communicationfee" column="communication_fee" />
<result property="actionlabels" column="action_labels" />
<result property="netscene" column="net_scene" />
</resultmap>
<resultmap id="productresultmap"
type="com.mchuan.fastmarketplat.b.entity.marketplanproduct">
<id property="id" column="product_id" />
<result property="coveramount" column="cover_amount" />
</resultmap>
<resultmap id="activityresultmap"
type="com.mchuan.fastmarketplat.b.entity.useractivity">
<id column="ac_id" property="id" />
<result column="activity_id" property="activityid" jdbctype="integer" />
<result column="cover_url" property="coverurl" jdbctype="varchar" />
<result column="activity_url" property="activityurl" jdbctype="varchar" />
<result column="view_url" property="viewurl" jdbctype="varchar" />
<result column="create_time" property="createtime" />
<result column="update_time" property="updatetime" />
</resultmap>
<resultmap id="ideadataresultmap"
type="com.mchuan.fastmarketplat.b.entity.marketplanideadata">
<id property="id" column="idea_data_id" />
<result property="content" column="content" />
<result property="linkurl" column="link_url" />
<!-- ideadata关联属性 -->
<association property="useractivity"
javatype="com.mchuan.fastmarketplat.b.entity.useractivity" resultmap="activityresultmap" />
</resultmap>
<resultmap id="baseresultmap" type="com.mchuan.fastmarketplat.b.entity.marketplan">
<id column="id" property="id" jdbctype="integer" />
<result column="plan_name" property="planname" jdbctype="varchar" />
<result column="budget" property="budget" jdbctype="decimal" />
<result column="actual_budget" property="actualbudget"
jdbctype="decimal" />
<result column="demand_type" property="demandtype" jdbctype="varchar" />
<result column="start_date" property="startdate" />
<result column="end_date" property="enddate" />
<result column="create_status" property="createstatus"
jdbctype="integer" />
<result column="create_time" property="createtime" />
<result column="update_time" property="updatetime" />
<result column="note" property="note" jdbctype="varchar" />
<result column="status" property="status" jdbctype="integer" />
<result column="destpage_url" property="destpageurl" jdbctype="varchar" />
<result column="is_award" property="isaward" jdbctype="integer" />
<result column="award_money" property="awardmoney" jdbctype="decimal" />
<result column="advertiser" property="advertiser" jdbctype="varchar" />
<result column="industry" property="industry" jdbctype="integer" />

<!-- marketplan关联属性 -->
<association property="user"
javatype="com.mchuan.fastmarketplat.b.entity.user" resultmap="userresultmap" />
<association property="marketplanlabel"
javatype="com.mchuan.fastmarketplat.b.entity.marketplanlabel"
resultmap="labelresultmap" />
<association property="marketplanproduct"
javatype="com.mchuan.fastmarketplat.b.entity.marketplanproduct"
resultmap="productresultmap" />
<association property="marketplanideadata"
javatype="com.mchuan.fastmarketplat.b.entity.marketplanideadata"
resultmap="ideadataresultmap" />
</resultmap>

以上所述是小编给大家介绍的 mybatis 中的一对一，一对多，多对多的配置原则示例代码，希望对大家有所帮助