Java로 서버를 작성하고 iPhone 앱 (Objective C)을 사용하여 통신하려고합니다. 연결이 완료되고 서버에 데이터를 쓸 수는 있지만 서버에서 데이터를 다시 읽을 수는 없습니다. 읽을 데이터가 있다는 알림이 표시되지만 비어 있습니다. 제가 생각하기에는 read:maxLength: 이부분에서 문제가 생긴것같습니다.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    [[UIApplication sharedApplication] setKeepAliveTimeout:600 handler:^(void) {
        NSLog(@"staying alive!");
        [[DABMultitaskingController sharedInstance] startTask];
    }];

CFReadStreamRef readStream;
CFWriteStreamRef writeStream;
CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)@"10.0.1.189", 4444, &readStream, &writeStream);

NSInputStream *inputStream = (NSInputStream *)readStream;
NSOutputStream *outputStream = (NSOutputStream *)writeStream;
[inputStream setDelegate:self];
[outputStream setDelegate:self];
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[inputStream open];
[outputStream open];

_dataToSend = [[NSData dataWithBytes:"This is a test" length:15] retain];

self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
return YES; }

- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent
{
    switch (streamEvent) {
        case NSStreamEventHasBytesAvailable: {
            NSLog(@"can read: %@", theStream);

        uint8_t *buffer;
        NSUInteger length;
        [(NSInputStream *)theStream getBuffer:&buffer length:&length]; //여기서 문제
        NSData *data = [NSData dataWithBytes:buffer length:length]; // 여기서 문제
        NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"bytes: %@", data);
        NSLog(@"string: %@", string);

        break;
    }
    case NSStreamEventHasSpaceAvailable: {
        NSLog(@"can write: %@", theStream);

        if (_dataToSend != nil) {
            NSLog(@"write: %@", _dataToSend);
            [(NSOutputStream *)theStream write:[_dataToSend bytes] maxLength:[_dataToSend length]];
            [_dataToSend release];
            _dataToSend = nil;
        }

        break;
    }
    case NSStreamEventOpenCompleted: {
        NSLog(@"open complete: %@", theStream);

        break;
    }
    case NSStreamEventErrorOccurred: {
        NSLog(@"error occurred: %@", theStream);

        break;
    }
    case NSStreamEventEndEncountered: {
        NSLog(@"end encountered: %@", theStream);

        break;
    }
    default:
        break;
} }