mybatis中 <if test=>等于的条件怎么写

<update id="updateGoodsShelf" parameterType="java.lang.String">
update
integral_goods
set
<if test='shelfFlag == "1"'>
shelf_flag = ${@com.pisen.cloud.luna.ms.jifen.base.domain.IntegralGoods@SHELF_ON}
</if>
<if test='shelfFlag == "0"'>
shelf_flag = ${@com.pisen.cloud.luna.ms.jifen.base.domain.IntegralGoods@SHELF_OFF}
</if>
where
uid
IN
<foreach collection="list" item="item" index="index" open="(" separator="," close=")">
#{item}
</foreach>
</update>