iOS开发——网络编程Swift篇&（七）NSURLSession详解

NSURLSession详解

     // MARK: - /* 使用NSURLSessionDataTask加载数据 */
     func sessionLoadData()
     {
         //创建NSURL对象
         var url:NSURL! = NSURL(string: "http://m.weather.com.cn/data/101010100.html")

         //创建请求对象
         var request : NSURLRequest = NSURLRequest(URL: url)

         let session = NSURLSession.sharedSession()

         var dataTask = session.dataTaskWithRequest(request, completionHandler: { (var data:NSData?, var response:NSURLResponse?, var error:NSError?) -> Void in

             //返回错误信息情况
             if (error != nil)
             {
                 println(error?.code)
                 println(error?.description)
             }else
             {
                 var jsonString = NSString(data: data!, encoding: NSUTF8StringEncoding)
                 println(jsonString)
             }
         }) as NSURLSessionTask

         //使用resume方法启动任务
         dataTask.resume()
     }

     // MARK: - /* 使用NSURLSessionDataTask下载文件  ---- 简单下载，不需要知道下载进度 */
     func sessionSimpleDownload()
     {
         //下载地址
         var url = NSURL(string: "http://www.iphonetrain.com/shop/data/ios/201404/source/2809080296130100.jpg")
         //请求
         var request = NSURLRequest(URL: url!)
         //连接
         var session = NSURLSession.sharedSession()
         //下载任务
         var downloadTask = session.downloadTaskWithRequest(request, completionHandler: { (var location:NSURL?,var response:NSURLResponse?, var error:NSError?) -> Void in

             // 输出下载文件原来的存放目录
             println("location: \(location)")

             //location位置转换
             var locationPath = location?.path

             //拷贝到我们自己目录中
             let documents:String = NSHomeDirectory() + "/Documents/1.png"

             // 创建文件管理器
             var fileManager :NSFileManager = NSFileManager.defaultManager()
             fileManager.moveItemAtPath(locationPath!, toPath: documents, error: nil)
             println("location: \(documents)")
         })

         //使用resume方法启动任务
         downloadTask.resume()
     }

     // MARK: - /* 使用NSURLSessionDataTask下载文件  ---- 获取进度 */
     //创建一个下载模式--单利实现
     func currentSession()->NSURLSession{

         var predicate:dispatch_once_t =
         var currentSession:NSURLSession? = nil

         dispatch_once(&predicate,{

             var config = NSURLSessionConfiguration.defaultSessionConfiguration()

             currentSession = NSURLSession(configuration: config, delegate: self, delegateQueue: nil)
             }
         )
         return currentSession!
     }

     func sessionSeniorDownload()
     {
         //下载地址
         var url = NSURL(string: "http://www.iphonetrain.com/shop/data/ios/201404/source/2809080296130100.jpg")
         //请求
         var request = NSURLRequest(URL: url!)

         //连接
         var session = currentSession() as NSURLSession

         //下载任务
         var downloadTask = session.downloadTaskWithRequest(request)

         //使用resume方法启动任务
         downloadTask.resume()
     }

      // MARK: - NSURLSessionDownloadDelegate
     func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didFinishDownloadingToURL location: NSURL)
     {
         //下载结束
         println("下载结束")

     }
     func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64)
     {
         //获取进度
          var written:CGFloat = (CGFloat)(bytesWritten)
          var total:CGFloat = (CGFloat)(totalBytesExpectedToWrite)

         var pro:CGFloat = written / total
         println("下按进度：\(pro)")
     }
     func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didResumeAtOffset fileOffset: Int64, expectedTotalBytes: Int64)
     {
         //下载偏移，主要用于暂停续传
     }

     // MARK: -  /* 使用NSURLSessionDataTask上传文件 */
     func sessionUpload()
     {
         //上传的位置地址
         var url = NSURL(string: "http://www.iphonetrain.com/shop/data/")

         //请求
         var request = NSURLRequest(URL: url!)

         //连接
         var session = NSURLSession.sharedSession()

         //上传数据流
         let documents:String = NSHomeDirectory() + "/Documents/1.png"
         var imgData = NSData(contentsOfFile: documents)

         var uploadTask = session.uploadTaskWithRequest(request, fromData: imgData, completionHandler: { (var data:NSData?, var response:NSURLResponse?, var error:NSError?) -> Void in

             //上传完毕之后判断
             println("上传完毕")
         })

         //使用resume方法启动任务
         uploadTask.resume()
     }