IOS SWIFT 网络请求JSON解析 基础一

前言：移动互联网时代，网络通信已经是手机端必不可少的功能。应用中也必不可少地使用了网络通信，增强客户端与服务器交互。使用NSURLConnection实现HTTP的通信。NSURLConnection 提供了异步请求和同步请求两种通信方式。同步请求数据会造成主线程阻塞，通常在请求大数据或网络不通畅时不建议使用。

不管同步请求还是异步请求，建立通信的步骤是一样的：

1 创建NSURL

2 创建NSURLRequest

3 创建NSURLConnection

当NSURLConnection 创建成功后，就会创建一个HTTP连接。异步请求和同步请求的区别是：创建了异步请求，用户可以做其他的操作，请求会再另一个线程执行，通信结果及过程会在回调函数中执行。同步请求则不同，需要请求结束用户才能做其他的操作。

import UIKitclass ViewController: UIViewController,NSURLConnectionDataDelegate { var jsonData = NSMutableData() override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib. //SynchronousRequest()
//AsynchronousRequest()
} //同步请求
func SynchronousRequest() -> Void {
//创建需要求的NSURL
var url : NSURL! = NSURL(string: "http://m.weather.com.cn/mweather/101010100.html")
//创建请求对象
var request = NSURLRequest(URL: url)
//定义响应对象
var response : NSURLResponse?
//定义错误对象
var error : NSError?
//发出请求
var data = NSURLConnection.sendSynchronousRequest(request, returningResponse: &response, error: &error) if (error != nil) {
//处理错误
println(error?.code)
println(error?.description)
} else {
var josnstring = NSString(data: data!, encoding: NSUTF8StringEncoding)
//转为字符串
println(josnstring)
} } //异步请求
func AsynchronousRequest() -> Void {
//创建需要求的NSURL
var url : NSURL! = NSURL(string: "http://m.weather.com.cn/mweather/101010100.html")
//创建请求对象
var request = NSURLRequest(URL: url)
//创建连接
var connection = NSURLConnection(request: request, delegate: self)
//暂时理解不透彻，待深入了解
connection?.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSRunLoopCommonModes)
//开始
connection?.start()
} //将要发送请求
func connection(connection: NSURLConnection, willSendRequest request: NSURLRequest, redirectResponse response: NSURLResponse?) -> NSURLRequest? {
return request
} //接收响应
func connection(connection: NSURLConnection, didReceiveResponse response: NSURLResponse) { } //收到数据
func connection(connection: NSURLConnection, didReceiveData data: NSData) {
self.jsonData.appendData(data)
} //需要新的内容流
func connection(connection: NSURLConnection, needNewBodyStream request: NSURLRequest) -> NSInputStream? {
return request.HTTPBodyStream
} //发送数据请求
func connection(connection: NSURLConnection, didSendBodyData bytesWritten: Int, totalBytesWritten: Int, totalBytesExpectedToWrite: Int) { } //缓存响应
func connection(connection: NSURLConnection, willCacheResponse cachedResponse: NSCachedURLResponse) -> NSCachedURLResponse? {
return cachedResponse
} //请求结束
func connectionDidFinishLoading(connection: NSURLConnection) {
//请求的结果
var jsonstring = NSString(data: self.jsonData, encoding: NSUTF8StringEncoding) //转为字符串 //println(jsonstring) //解析json
let dict : AnyObject? = NSJSONSerialization.JSONObjectWithData(self.jsonData, options: NSJSONReadingOptions.AllowFragments, error: nil) var dic = dict as! NSDictionary let weatherinfo = dic.objectForKey("weatherinfo") as! NSDictionary
let city = weatherinfo.objectForKey("city") as! String
let date_y = weatherinfo.objectForKey("date_y") as! String
let temp1 = weatherinfo.objectForKey("temp1") as! String } override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated. }}