ios5 NSURLConnection异步连接实现

//风火轮实现

UIActivityIndicatorView*activityView=[[UIActivityIndicatorViewalloc]initWithFrame:CGRectMake(150,30,100,100)];

   [activityView setBackgroundColor:[UIColor lightGrayColor]];

    [self.viewaddSubview:activityView];

    [activityViewstartAnimating];

 NSURLRequest*request=[[NSURLRequestalloc]initWithURL:[NSURLURLWithString:@"http://www.youku.com/"]];

   NSOperationQueue*operationQueue=[[NSOperationQueuealloc]init];

   [NSURLConnectionsendAsynchronousRequest:request 

                                queue:operationQueue 

                      completionHandler:^(NSURLResponse*urlResponce,NSData*data,NSError*error)

     {

       if(error)

     {

     

       NSLog(@"error:\n%@",error);

       return ;

     }

        [activityViewstopAnimating];

     //NSData转换成NSString

       NSString*  aStr = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];

       NSLog(@"getdata%@",data);

      NSLog(@"result%@",aStr);

     }

     ];

    [operationQueuerelease];

//异步请求

 NSURLRequest*urlRequest=[[NSURLRequestalloc]initWithURL:[NSURLURLWithString:@"http://www.youku.com/"]];

    NSURLResponse*urlResponce=nil;

    NSError*error=nil;

    NSData*data=[NSURLConnection sendSynchronousRequest:urlRequestreturningResponse:&urlResponceerror:&error];

    NSLog(@"data%@",data);

    if (error) {

      NSLog(@"error%@",error);

      return;

    }