NSURLConnection, NSURLRequest, NSURL 을 간단하게 사용 합 니 다.

//
//  HttpDemo.h
//  MyAddressBook
//
//  Created by hherima on 14-6-23.
//  Copyright (c) 2014 . All rights reserved.
//
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface HttpDemo : NSObject<NSURLConnectionDelegate, NSURLConnectionDataDelegate>
{
    NSMutableData *receivedData;
    NSURLConnection *theConncetion;
}
@end

//
//  HttpDemo.m
//  MyAddressBook
//
//  Created by hherima on 14-6-23.
//  Copyright (c) 2014 . All rights reserved.
//

#import "HttpDemo.h"
@implementation HttpDemo
/*
 NSURLConnection             URL  ,                   ，       delegate               
 
   ：
 1、     NSURL
 2、   NSURL  NSURLRequest，             
 3、  NSURLConnection  ，  NSURLRequest   delegate  
       ，    nil,           NSMutalbeData         
 */
- (id)init {
    self = [super init];
    // Override point for customization after application launch.
    NSURLRequest* theRequest = [NSURLRequest requestWithURL:
                                [NSURL URLWithString:@"http://www.baidu.com"]//
                                                cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
                                            timeoutInterval:60.0];
    //   initWithRequest: delegate：    ，       ，   （delegate）
    //  connectionDidFinishLoading：  connection：didFailWithError：    
    //           cancel：       
    theConncetion=[[NSURLConnection alloc]
                   initWithRequest:theRequest delegate:self];
    if(theConncetion)
    {
        //  NSMutableData
        receivedData = [NSMutableData data];
    }
    else
    {
        //    ;
    }
    
    return self;
}


//               NSURLResponse      ，         connection：didReceiveResponse：  ，        NSURLResponse            ，mime  ，                

//【   】，               connection：didReceiveResponse：                   （    mime  ），                    ，         
-(void)connection:(NSURLConnection *)connectiondidReceiveResponse:(NSURLResponse*)response
{
    [receivedData setLength:0];
}


//        ，       ，       connection：didReceiveData：                  ，         
-(void) connection:(NSURLConnection*)connection didReceiveData:(NSData *)data
{
    [receivedData appendData:data];
}


//         connection：didFailWithError   ，              
-(void)connection:(NSURLConnection*)connection didFailWithError:(NSError*)error
{
    theConncetion = nil;
    
    NSLog(@"Connection failed! Error - %@ %@",[error localizedDescription],[[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
    
}
//      ,  ，           ，     connectionDidFinishLoading：              ，       ，       
-(void)connectionDidFinishLoading:(NSURLConnection*)connection
{
    //do something with the data
    NSString *s = [[NSString alloc] initWithData:receivedData encoding:NSUTF8StringEncoding];
    NSLog(@"succeeded %@",s);
    theConncetion = nil;
    [receivedData setLength:0];
}
@end