java - struts2でjsonオブジェクトではなく配列のみを返す方法

Question

<action name="commissioner_info" method="commissioner_info" class="foo.bar.AdminInfoAction">
    <result name="json" type="json">    
        <param name="includeProperties">
            commissioner_info\[\d+\]\.fname,
            commissioner_info\[\d+\]\.designation,        
            commissioner_info\[\d+\]\.pathlocation
        </param>
    </result>
</action>

結果を与える上記のコード：

{"commissioner_info":[{"designation":"IG1","fname":"BS  Bassi ","pathlocation":"http:\/\/103.231.125.106\/nesos\/imagerepresentatives\/151021104556Bhim.jpg"}]}

しかし、jsonオブジェクトではなく配列のみが必要です

[{"designation":"IG1","fname":"BS  Bassi ","pathlocation":"http:\/\/103.231.125.106\/nesos\/imagerepresentatives\/151021104556Bhim.jpg"}]