Ios 使用[]时，Swift JSON会中断

在我正在进行的一个简单项目中，我试图从url获取JSON数据并将其打印出来。然而，Swift似乎不喜欢[]中包装的JSON，即使它是有效的JSON

这是我获取/解析JSON的Swift代码

func startConnection(){
    let urlName: String = "http://SOMEURL.net/jsonout.php"
    var url: NSURL = NSURL(string: urlName)!
    var request: NSURLRequest = NSURLRequest(URL: url)
    var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)!
    connection.start()
}

func connection(connection: NSURLConnection!, didReceiveData data: NSData!){
    self.data.appendData(data)
}
func connectionDidFinishLoading(connection: NSURLConnection!) {
    var err: NSError
    // throwing an error on the line below (can't figure out where the error message is)
    var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
    println(jsonResult)
}

下面是一个JSON示例

{   
  "Accept-Language": "en-US,en;q=0.5",
  "Host": "headers.jsontest.com",
  "Referer": "http://www.jsontest.com/",
  "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:36.0) Gecko/20100101 Firefox/36.0",
  "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
}

以及导致应用程序崩溃的示例

[
  {
      "artist": "Led Zeppelin",
      "requestname": "test",
      "title": "Stairway To Heaven"
  },
  {
      "artist": "Modest Mouse",
      "requestname": "test",
      "title": "Lampshades On Fire"
  }
]

---

在第二种情况下，您传递了一个数组，但仍然将其强制转换为

NSDictionary

更改以下代码：

var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary

到

var jsonResult: NSArray = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSArray