var url = NSURL(string: "http://www.weather.com.cn/data/sk/101120501.html")

        var data = http://www.mamicode.com/NSData(contentsOfURL: url!, options: NSDataReadingOptions.DataReadingUncached, error: nil)

        var json : AnyObject! = NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions(), error: nil)

        var weatherinfo: AnyObject? = json.objectForKey("weatherinfo")

        var city: AnyObject? = weatherinfo?.objectForKey("city")

        //  println(city)

swift 官方获取JSON 数据方法