ObjectiveC에서 WebService를 동기화하는 방법

 //    ,  returnData   
        NSData *returnData = [NSURLConnection sendSynchronousRequest:urlRequest                                                      returningResponse:nil error:nil];

        NSString * rtnString =  [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];
        DLog(@" ， ：%@", rtnString);

비동기적으로 호출하는 방법은 이것을 볼 수 있다
http://blog.csdn.net/remote_roamer/article/details/7481255

    RemoteMethodCall * rpc = [[[RemoteMethodCall alloc] init] autorelease];
    NSMutableURLRequest *urlRequest = [rpc getCustomerActivation:self.udid];
    
    // 
    NSURLConnection *theConnection = [[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self] autorelease];
    
    theConnection = nil;

다음과 같은 몇 가지 비동기적인 방법을 실현해야 한다
- (void)connection:(NSURLConnection*)connection didReceiveResponse:(NSHTTPURLResponse*)response
- (void)connection:(NSURLConnection*)connection didReceiveData:(NSData*)data
- (void)connection:(NSURLConnection*)connection didFailWithError:(NSError*)error
- (void)connectionDidFinishLoading:(NSURLConnection *)connection