Swift中用NSURLConnection解析URL，并解析Jason数据

使用NSURL的代理方法

用NSMutableData来保存每次获得的数据

@lazy var data = NSMutableData()

用NSJSONNSerialization来解析数据

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

完整的代码

import UIKit

class ViewController: UIViewController, NSURLConnectionDelegate {

    lazy var data = NSMutableData()

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)

        let urlPath: String = "http://www.baidu.com"
        var url: NSURL = NSURL(string: urlPath)
        var request: NSURLRequest = NSURLRequest(URL: url)
        var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)
        connection.start()

}  

     override func didReceiveMemoryWarning() {
         super.didReceiveMemoryWarning()        
      }

      func connection(connection: NSURLConnection!, didReceiveData data: NSData!){
         self.data.appendData(data)
        }        

      func connectionDidFinishLoading(connection: NSURLConnection!) {
          var err: NSError        // 如果转换有错误，错误信息保存在err中

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