Parse Json with Swift in iOS Programming

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // load file json
        let urlString = "http://www.learnswiftonline.com/Samples/subway.json"
        let url : NSURL = NSURL(string: urlString)!
        let urlSession = NSURLSession.sharedSession()

        // query url
        let jsonQuery = urlSession.dataTaskWithURL(url) { (data, reponse, error) in
            if (error != nil){
                print("\(error!.localizedDescription)");
            }
            var err : NSError?
            var jsonResult = (try! NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers)) as! NSDictionary

            if (err != nil) {
                print("error : \(err?.localizedDescription)")
            }

            let jsonData : NSArray! = jsonResult["stations"] as! NSArray
            if jsonData != nil {
                print("\(jsonData)");
            }

            for var element in jsonData {
                print((element["stationName"]))
                print((element["buildYear"]))
            }
        }
        jsonQuery.resume()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}