參考文件：apache ognl 參考文件

假設map.id有兩種型別，String或Array（別抬槓，我就想這麼處理）
之前的寫法：

<where>
	<if test="map.id !=null and map.id != ''">
	AND asset.id in
	    <foreach collection="map.id" item="item" open="(" close=")" separator=",">#{item}</foreach>
	</if>
</where>

這樣如果傳進來的id是String型，將會報錯：
Error evaluating expression ‘xxx’. Return value (xxx) was not iterable.

那麼如何在mapper.xml裡面判斷兩種屬性呢

<where>
    <choose>
        <when test="map.id instanceof String">
        AND asset.id = #{map.id}
        </when>
        <otherwise>
            <if test="map.id !=null and map.id != ''">
            AND asset.id in
                <foreach collection="map.id" item="item" open="(" close=")" separator=",">#{item}</foreach>
            </if>
        </otherwise>
    </choose>
</where>