Swift3.0：NSURLConnection的使用

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 - NSURLConnectionDataDelegate
extension 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 UIKit

class 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 - NSURLConnectionDataDelegate
extension 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);
        }
    }
}