PageHelper插件实现一对多查询时的分页问题

<resultmap id= "basemap" type= "com.xx.oo.activity" >

   <id column= "id" property= "id" jdbctype= "integer" />

     ....

</resultmap>

<resultmap id= "resultmap" type= "com.xx.oo.activity" extends = "basemap" >

   <collection property= "templates" oftype= "com.xx.oo.template" >

     <id column= "pt_id" property= "id" jdbctype= "integer" />

     <result column= "pt_title" property= "title" jdbctype= "varchar" />

   </collection>

</resultmap>

<resultmap id= "richresultmap" type= "com.xx.oo.activity" extends = "basemap" >

   <!--property：对应javabean中的字段-->

   <!--oftype：对应javabean的类型-->

   <!--javatype：对应返回值的类型-->

   <!--column：对应数据库column的字段，不是javabean中的字段-->

   <!--select：对应查询子集的sql-->

   <collection property= "templates" oftype= "com.xx.oo.template" javatype= "java.util.list" column= "id" select= "querytemplatebyid" >

     <id column= "pt_id" property= "id" jdbctype= "integer" />

     <result column= "pt_title" property= "title" jdbctype= "varchar" />

   </collection>

</resultmap>

<resultmap id= "template" type= "com.xx.oo.template" >

   <id column= "pt_id" property= "id" jdbctype= "integer" />

   <result column= "pt_title" property= "title" jdbctype= "varchar" />

</resultmap>

<!--这里的#{id}参数就是collection中定义的column字段-->

<select id= "querytemplatebyid" parametertype= "java.lang.integer" resultmap= "template" >

   select id pt_id, title pt_title

   from t_activity_template where is_delete= 0 and activity_id = #{id}

   order by sort_number desc

</select>

<select id= "querybypage" parametertype= "com.xx.oo.activitypagerequest" resultmap= "richresultmap" >

   select t.*,t1.real_name creator_name

   from t_activity t

   left join user t1 on t1.user_id = t.creator

   <where>

     t.is_delete = 0

     < if test= "criteria != null and criteria.length()>0" >and (t.activity_name like concat( "%" ,#{criteria}, "%" ))</ if >

   </where>

   order by t.id desc

</select>

<select id= "querybyid" parametertype= "java.lang.integer" resultmap= "resultmap" >

   select t.*, t6.id pt_id, t1.title pt_title

   from t_activity t

   left join t_activity_template t1 on t.id=t6.activity_id and t1.is_delete= 0

   where t.is_delete = 0 and t.id = #{id}

</select>