(转 )
头文件noteHttp.h1 #import2 @interface NoteHttp : NSObject{ 3 //urlfbfh 4 NSString *urlString; 5 //下载的数据 6 NSMutableData *dataNote; 7 } 8 @property(nonatomic,retain) NSString *urlString; 9 @property(nonatomic,retain)NSMutableData *dataNote;10 -(void)down;11 @end
实现文件 noteHttp.m
1 #import "NoteHttp.h" 2 @implementation NoteHttp 3 @synthesize urlString,dataNote,noteXml; 4 - (id)init { 5 self = [super init]; 6 if (!self) { 7 [self release]; 8 return nil; 9 }10 urlString=[[NSString alloc]init];11 dataNote=[[NSMutableData alloc]init];12 return self;13 }14 -(void)down{15 //http地址16 urlString=@"http://192.168.67.3:8080/Todo/note.xml";17 //转成NSURL，18 NSURL *url=[NSURL URLWithString:urlString];19 //负载请求20 NSURLRequest *request=[[NSURLRequest alloc]initWithURL:url];21 //异步请求，通过一个delegate来做数据的下载以及Request的接受等等消息，此处delegate:self，所以需要本类实现一些方法，并且定义receivedData做数据的接受22 NSURLConnection *connection=[[NSURLConnection alloc]initWithRequest:request delegate:self];23 [connection release];24 [request release];25 /*26 但是异步模式下带来了一个新的问题，很多情况下，网络请求不在主线程，或者界面等待网络结果，不在主线程的时候，调用线程如果生命周期over，下面这些可能都没有调用到，导致得不到想要得效果，所以需要在NSURLConnection请求后面加点东西来阻塞27 while(!finished) {28 29 [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDatedistantFuture]];30 31 }32 */33 }34 //从网络上下载的数据,直到数据全部下载完成35 -(void)connection:(NSURLConnection *)connection didReceiveData:(NSMutableData *)data{36 [self.dataNote appendData:data];37 }38 //http交互正常，完成。39 - (void)connectionDidFinishLoading:(NSURLConnection *)connection40 {41 //沙盒路径42 NSArray *paths= NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);43 NSString *documentsDirectory = [paths objectAtIndex:0];44 NSString *path = [documentsDirectory stringByAppendingPathComponent:@"note.xml"];45 46 //当完成交互，也就是说数据下载完成时，就创建该文件47 [[NSFileManager defaultManager]createFileAtPath:path contents:dataNote attributes:nil];48 }49 50 //网络连接不成功，出现异常。51 - (void)connection:(NSURLConnection *)connection 52 didFailWithError:(NSError *)error53 {54 //如果出现异常，弹出对话框给出原因55 UIAlertView *errorAlert = [[UIAlertView alloc]56 initWithTitle: [error localizedDescription]57 message: [error localizedFailureReason]58 delegate:nil59 cancelButtonTitle:@"OK"60 otherButtonTitles:nil];61 [errorAlert show];62 [errorAlert release];63 64 }65 -(void)dealloc{66 [urlString release];67 [dataNote release];68 [super dealloc];69 }70 @end