IOS 网络通信 异步请求

//异步请求
NSURLConnection.sendAsynchronousRequest(NSURLRequest(URL:NSURL(string: "http://blog.csdn.net/czherui")!), queue: NSOperationQueue()) {
(res:NSURLResponse?, data:NSData?, error:NSError?) -> Void in

if let _ = error{
print("出错了")
}else
{
print(NSString(data: data!, encoding:NSUTF8StringEncoding))
}
}
//IOS9.0后，就打算废弃NSURLConnection，使用 NSURLSession

//        func usingNSURLSession(){
let session = NSURLSession.sharedSession()
let request = NSURLRequest(URL: NSURL(string: "http://blog.csdn.net/czherui")!)
let task = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in
//                let string = NSString(data: data!, encoding: NSUTF8StringEncoding)

print(NSString(data: data!, encoding: NSUTF8StringEncoding))
})
task.resume()

}