mybatis oracle 批量插入

   <insert id="insertuser" parameterType="java.util.List" useGeneratedKeys="false" >
        insert into user
        (
            username,
            sex,
            age
        )
        <foreach close=")" collection="list" item="item" index="index" open="(" separator="union all">
            select
                #{item.username},
                #{item.sex},
                #{item.age}
            from dual 
        </foreach>
    </insert>