NSError(domain: urlString, code: httpRes.statusCode, userInfo: nil)：
//1.创建NSURL对象
let url = NSURL(string: urlString)
//2.创建NSURLRequest对象
let request = NSURLRequest(URL: url!)
//3.NSURLSession对象
let session = NSURLSession.sharedSession()
//4.task
let task = session.dataTaskWithRequest(request) { (data, response, error) in
if error != nil {
//下载失败
self.delegate?.sessionDownloader(self, didFailWithError: error)
}else{
//服务器成功接收请求
let httpRes = response as! NSHTTPURLResponse
if httpRes.statusCode == 200 {
//成功返回数据
self.delegate?.sessionDownloader(self, didFinishWithData: data)
}else{
//请求参数有错误
let error = NSError(domain: urlString, code: httpRes.statusCode, userInfo: nil)
self.delegate?.sessionDownloader(self, didFailWithError: error)
}
}
}
