一、介绍
应用中也不必不可少的会使用网络通信，增强客户端和服务器的交互，可以使用NSURLConnection实现http通信。
NSURLConnection提供了异步请求和同步请求两种请求方式。同步请求数据会造成主线程阻塞，通常不建议在请求大数据或者网络不畅时使用。
不管是同步请求还是异步请求，建立通信的步骤都是一样的：
1、创建URL对象； 2、创建URLRequest对象； 3、创建NSURLConnection连接；
NSURLConnection创建成功后，就创建了一个http连接。异步请求和同步请求的区别是：
1、创建了异步请求，用户还可以做其他的操作，请求会在另一个线程执行，通信结果及过程会在回调函数中执行； 2、创建了同步请求，用户需要在请求结束后才能做其他的操作，这也是通常造成主线程阻塞的原因。
二、示例
同步请求数据方法如下:
//同步请求数据方法如下：func httpSynchronousRequest(){ // 1、创建URL对象； let url:URL! = URL(string:"http://api.iclient.ifeng.com/ClientNews?id=SYLB10,SYDT10"); // 2、创建Request对象； let urlRequest:URLRequest = URLRequest(url:url); // 3、发起NSURLConnection连接 NSURLConnection.sendAsynchronousRequest(urlRequest, queue: .main) { (response:URLResponse?, data:Data?, error:Error?) in if(error != nil){ print(error?.localizedDescription); }else{ //let jsonStr = String(data: data!, encoding:String.Encoding.utf8); //print(jsonStr) do { let dic = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.allowFragments) print(dic) } catch let error{ print(error.localizedDescription); } } } } 异步请求数据方法如下：
//在控制器声明一个全局的变量，存储解析到的data数据 var jsonData:NSMutableData = NSMutableData()
//异步请求数据方法如下：func httpAsynchronousRequest(){ // 1、创建URL对象； let url:URL! = URL(string:"http://api.iclient.ifeng.com/ClientNews?id=SYLB10,SYDT10"); // 2、创建Request对象； let urlRequest:URLRequest = URLRequest(url:url); // 3、发起NSURLConnection连接 let conn:NSURLConnection? = NSURLConnection(request:urlRequest,delegate:self) conn?.schedule(in: .current, forMode: .defaultRunLoopMode) conn?.start()} // MARK - NSURLConnectionDataDelegateextension ViewController:NSURLConnectionDataDelegate{ func connection(_ connection: NSURLConnection, willSend request: URLRequest, redirectResponse response: URLResponse?) -> URLRequest? { //发送请求 return request; } func connection(_ connection: NSURLConnection, didReceive response: URLResponse) { //接收响应 } func connection(_ connection: NSURLConnection, didReceive data: Data) { //收到数据 self.jsonData.append(data); } func connection(_ connection: NSURLConnection, needNewBodyStream request: URLRequest) -> InputStream? { //需要新的内容流 return request.httpBodyStream; } func connection(_ connection: NSURLConnection, didSendBodyData bytesWritten: Int, totalBytesWritten: Int, totalBytesExpectedToWrite: Int) { //发送数据请求 } func connection(_ connection: NSURLConnection, willCacheResponse cachedResponse: CachedURLResponse) -> CachedURLResponse? { //缓存响应 return cachedResponse; } func connectionDidFinishLoading(_ connection: NSURLConnection) { //请求结束 //let jsonStr = String(data: self.jsonData as Data, encoding:String.Encoding.utf8); //print(jsonStr) do { let dic = try JSONSerialization.jsonObject(with: self.jsonData as Data, options: JSONSerialization.ReadingOptions.allowFragments) print(dic) } catch let error{ print(error.localizedDescription); } }}
三、解析结果：
( { currentPage = 1; expiredTime = 180000; item = ( { comments = 134; commentsUrl = "http://inews.ifeng.com/ispecial/913/index.shtml"; commentsall = 1818; documentId = "imcp_crc_1063216227"; id = "http://api.iclient.ifeng.com/TopicApiForCmpp?topicid=913&json=y"; link = { type = topic2; url = "http://api.iclient.ifeng.com/TopicApiForCmpp?topicid=913&json=y"; weburl = "http://api.iclient.ifeng.com/TopicApiForCmpp?topicid=913"; }; online = 0; reftype = editor; staticId = "client_special_913"; style = { attribute = "\U4e13\U9898"; backreason = ( "\U5185\U5bb9\U8d28\U91cf\U5dee", "\U65e7\U95fb\U3001\U91cd\U590d", "\U6807\U9898\U515a" ); view = titleimg; }; styleType = topic; thumbnail = "http://d.ifengimg.com/w198_h141_q100/p3.ifengimg.com/cmpp/2017/04/02/77c9cacd305fbad2554272f27dfc42e2_size39_w168_h120.jpg"; title = "\U4e60\U8fd1\U5e73\U201c\U4e09\U4f1a\U201d\U5c3c\U5c3c\U65af\U6258"; type = topic2; }, { ........... ........... ...........}
四、源码：
//// ViewController.swift// NetWorkTest//// Created by 夏远全 on 2017/4/3.// Copyright © 2017年 夏远全. All rights reserved.///* NSURLConnection的使用： */import UIKitclass ViewController: UIViewController { var jsonData:NSMutableData = NSMutableData() override func viewDidLoad() { super.viewDidLoad() //httpSynchronousRequest() //httpAsynchronousRequest() } //同步请求数据方法如下： func httpSynchronousRequest(){ // 1、创建NSURL对象； let url:URL! = URL(string:"http://api.iclient.ifeng.com/ClientNews?id=SYLB10,SYDT10"); // 2、创建Request对象； let urlRequest:URLRequest = URLRequest(url:url); // 3、发起NSURLConnection连接 NSURLConnection.sendAsynchronousRequest(urlRequest, queue: .main) { (response:URLResponse?, data:Data?, error:Error?) in if(error != nil){ print(error?.localizedDescription); }else{ //let jsonStr = String(data: data!, encoding:String.Encoding.utf8); //print(jsonStr) do { let dic = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.allowFragments) print(dic) } catch let error{ print(error.localizedDescription); } } } } //异步请求数据方法如下： func httpAsynchronousRequest(){ // 1、创建NSURL对象； let url:URL! = URL(string:"http://api.iclient.ifeng.com/ClientNews?id=SYLB10,SYDT10"); // 2、创建Request对象； let urlRequest:URLRequest = URLRequest(url:url); // 3、发起NSURLConnection连接 let conn:NSURLConnection? = NSURLConnection(request:urlRequest,delegate:self) conn?.schedule(in: .current, forMode: .defaultRunLoopMode) conn?.start() }}// MARK - NSURLConnectionDataDelegateextension ViewController:NSURLConnectionDataDelegate{ func connection(_ connection: NSURLConnection, willSend request: URLRequest, redirectResponse response: URLResponse?) -> URLRequest? { //发送请求 return request; } func connection(_ connection: NSURLConnection, didReceive response: URLResponse) { //接收响应 } func connection(_ connection: NSURLConnection, didReceive data: Data) { //收到数据 self.jsonData.append(data); } func connection(_ connection: NSURLConnection, needNewBodyStream request: URLRequest) -> InputStream? { //需要新的内容流 return request.httpBodyStream; } func connection(_ connection: NSURLConnection, didSendBodyData bytesWritten: Int, totalBytesWritten: Int, totalBytesExpectedToWrite: Int) { //发送数据请求 } func connection(_ connection: NSURLConnection, willCacheResponse cachedResponse: CachedURLResponse) -> CachedURLResponse? { //缓存响应 return cachedResponse; } func connectionDidFinishLoading(_ connection: NSURLConnection) { //请求结束 //let jsonStr = String(data: self.jsonData as Data, encoding:String.Encoding.utf8); //print(jsonStr) do { let dic = try JSONSerialization.jsonObject(with: self.jsonData as Data, options: JSONSerialization.ReadingOptions.allowFragments) print(dic) } catch let error{ print(error.localizedDescription); } }}