Mybatis 中的一对一,一对多,多对多的配置原则示例代码_Java教程

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>