HTTP协议可以说在APP开发中太常见了，基本上哪里都有它的身影。今天简单讲解下Swift语言的HTTP的请求例子。

import UIKit  
  
@UIApplicationMain  
class AppDelegate: UIResponder, UIApplicationDelegate {  
                              
    var window: UIWindow?  
  
  
    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {  
        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)  
        // Override point for customization after application launch.  
        self.window!.backgroundColor = UIColor.whiteColor()  
        self.window!.makeKeyAndVisible()  
          
        var root=RootViewController()  
        self.window!.rootViewController=root  
          
          
          
        return true  
    }  
  
    func applicationWillResignActive(application: UIApplication) {  
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.  
        // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.  
    }  
  
    func applicationDidEnterBackground(application: UIApplication) {  
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.  
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.  
    }  
  
    func applicationWillEnterForeground(application: UIApplication) {  
        // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.  
    }  
  
    func applicationDidBecomeActive(application: UIApplication) {  
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.  
    }  
  
    func applicationWillTerminate(application: UIApplication) {  
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.  
    }  
  
  
}  

Controllner.swift

import UIKit  
  
class RootViewController: UIViewController {  
  
    var btn:UIButton?  
    var text:UITextField?  
    var lable:UILabel?  
  
    override func viewDidLoad() {  
        super.viewDidLoad()  
        //TextField  
        text=UITextField()  
        text!.frame=CGRectMake(20,30,self.view.bounds.size.width-40,30)  
        text!.placeholder="http://"  
        text!.borderStyle = .RoundedRect  
          
        //Button  
        btn=UIButton()  
        btn!.frame=CGRectMake(20, 80, 60, 30)  
        btn!.setTitle("HTTP",forState:.Normal)  
        btn!.addTarget(self,action:"onclick",forControlEvents:.TouchUpInside)  
        btn!.backgroundColor=UIColor.redColor()  
         
        //Lable  
        lable=UILabel()  
        lable!.frame=CGRectMake(0,120,self.view.bounds.size.width,self.view.bounds.size.height)  
        lable!.backgroundColor=UIColor.grayColor()  
        lable!.lineBreakMode = .ByWordWrapping;  
        lable!.numberOfLines=0  
          
        self.view.addSubview(self.btn)  
        self.view.addSubview(lable)  
        self.view.addSubview(text)  
  
        // Do any additional setup after loading the view.  
    }  
      
    func connection(connection:NSURLConnection!,didReceiveData data:NSData!){  
        var returnString:NSString?  
        returnString=NSString(data:data,encoding:NSUTF8StringEncoding)  
        println(returnString)  
        let jsonData = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary  
        var str="result:\n"+String(returnString!)  
          
        for (key,value) in jsonData{  
            str+="\n key-->\(key)"+" value=\(value) "  
        }  
        lable!.text=str  
          
    }  
      
    func onclick(){  
        var url:String=text!.text  
        if url==""  {  
//            let alert=UIAlertView()  
//            alert.title="Error"  
//            alert.message="please enter url!"  
//            alert.addButtonWithTitle("Ok")  
//            alert.show()  
            var urlString:String?="http://192.168.1.104:8080/Attendace/JsonController/getJson"  
            httpRequest(urlString!)  
  
        }else{  
            httpRequest(url)  
        }  
       
    
  
          
    }  
    func httpRequest( urlString:String){  
        var url:NSURL?  
        var requrst:NSURLRequest?  
        var conn:NSURLConnection?  
        url=NSURL.URLWithString(urlString)  
        requrst=NSURLRequest(URL:url)  
        conn=NSURLConnection(request: requrst,delegate: self)  
        println(conn)  
        if(conn){  
            println("http连接成功!")  
        }else{  
            println("http连接失败!")  
        }  
   
    }  
  
    override func didReceiveMemoryWarning() {  
        super.didReceiveMemoryWarning()  
        // Dispose of any resources that can be recreated.  
    }  
      
}  

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