freemarker遍历list处理第一个、最后一个元素

depts   positions   服务器返回的list 

<#list depts as entity>
    <#if entity_index = 0>第一个
     '[{"id":${entity.deptId},"pid":0,"status":1,"name":"${entity.deptName}"},'+
    </#if >
    '{"id":${entity.deptId},"pid":0,"status":1,"name":"${entity.deptName}"},' +
</#list>



<#list positions as entity>
    <#if entity_has_next>
        '{"id":${entity.id},"pid":${entity.deptid},"status":1,"name":"${entity.name}"},' +
<#else >最后一个
        '{"id":${entity.id},"pid":${entity.deptid},"status":1,"name":"${entity.name}"}]');
    </#if>
</#list>