ios swift http json

json解析测试：http://www.douban.com/j/app/radio/channels

 func get_data_from_url(url:String)    {        let httpMethod = "GET"        let timeout = 15        let url = NSURL(string: url)                let urlRequest = NSMutableURLRequest(URL: url,            cachePolicy: .ReloadIgnoringLocalAndRemoteCacheData,            timeoutInterval: 15.0)        let queue = NSOperationQueue()                NSURLConnection.sendAsynchronousRequest(            urlRequest,            queue: queue,            completionHandler: {(response: NSURLResponse!,                data: NSData!,                error: NSError!) in                if data.length > 0 && error == nil{                                        let json = NSString(data: data, encoding: NSASCIIStringEncoding)                   // let enc = CFStringConvertEncodingToNSStringEncoding(0x0632)                                      // let json  = NSString( data: data,  encoding:enc)                                      //  encoding:gbkEncoding                                        //  let json = NSString(data: data, encoding: NSUTF8StringEncoding)                                        //self.extract_json(json)                    println(json)                    // self.praseJson(data)                }else if data.length == 0 && error == nil{                    println("Nothing was downloaded")                } else if error != nil{                    println("Error happened = \(error)")                }            }        )    }

func praseJson(data: NSData) {        var json: AnyObject = NSJSONSerialization.JSONObjectWithData(data,options:NSJSONReadingOptions.AllowFragments,error:nil)!        var weatherInfos: AnyObject = json.objectForKey("channels")! //json结构字段名。        //var city:AnyObject = weatherInfo.objectForKey("name")!        // json 数组                for result in weatherInfos as NSArray {            var name = result.objectForKey("name") as NSString            println(name)        }        //        println(weatherInfo)    }