arrays-作为NSArray获取的json文件只包含第一个字符

我有一个json file如下所示：

[
  {
    "tn_newsid": 144377,
    "tn_midashi": "知床半島とオホーツク海の絶景が広がる",
    "tn_name": "北海道立オホーツク公園オートキャンプ場てんとらんど",
    "tn_ktel": "0152-45-27",
    "tn_url": "",
    "tn_kdo": 144.239526856306,
    "tn_ido": 43.9880220633556,
    "tn_im1name": "144377_1.jpg",
    "tn_im2name": "144377_2.jpg",
    "tn_im3name": "144377_3.jpg",
    "tn_im4name": "144377_4.jpg",
    "type": 0,
    "nico_recommended": 0
  },
  {
// etc ....

到现在为止，我一直在用截取的代码获取数据

seasonInfoService.seasonServerDataJson(jsoncompleted: { () in
let responseData: Data =  self.seasonInfoService.UpdateJsonString.data(using: String.Encoding.utf8)!
    do{
        let items = try JSONSerialization.jsonObject(with: responseData) as! Dictionary

但是json file开始于[所以我需要改变Dictionary到NSArray

因为我收到了这个错误代码

Could not cast value of type '__NSArrayI' (0x7fff86cd0128) to 'NSDictionary' 

我的代码现在看起来像

facilitiesService.facilitiesServerDataJson(urlToFetch: url_, jsoncompleted: { () in
let responseData: Data =  self.facilitiesService.UpdateJsonString.data(using: String.Encoding.utf8)!
    do{
        let items = try JSONSerialization.jsonObject(with: responseData) as! NSArray
        print(items)

但打印声明仅显示[，我如何才能将此更改为正确的词典列表？