인터넷에서 예제를 구해서 풀이하는데 

- (void) initNetworkCommunication {

CFReadStreamRef readStream;

CFWriteStreamRef writeStream;

CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)@"192.168.0.19", 3333, &readStream, &writeStream);

inputStream = (NSInputStream *)readStream;

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];

}

- (IBAction) sendMessage

{

    NSLog(@"%@", inputMessageField.text);

NSString *response  = [NSString stringWithFormat:@"%@\r\n", inputMessageField.text];

NSData *data = [[NSData alloc] initWithData:[response dataUsingEncoding:NSUTF8StringEncoding]];

    //

[outputStream write:[data bytes] maxLength:[data length]];

    

inputMessageField.text = @"";

}

- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent {

NSLog(@"stream event %i", streamEvent);

switch (streamEvent) {

case NSStreamEventOpenCompleted:

NSLog(@"Stream opened");

break;

case NSStreamEventHasBytesAvailable:

if (theStream == inputStream) {

uint8_t buffer[1024];

int len;

while ([inputStream hasBytesAvailable]) {

len = [inputStream read:buffer maxLength:sizeof(buffer)];

if (len > 0) {

NSString *output = [[NSString alloc] initWithBytes:buffer length:len encoding:NSUTF8StringEncoding];

if (nil != output) {

NSLog(@"server said: %@", output);

[self messageReceived:output];

}

}

}

}

break;

case NSStreamEventErrorOccurred:

NSLog(@"Can not connect to the host!");

break;

case NSStreamEventEndEncountered:

            [theStream close];

            [theStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];

            [theStream release];

            theStream = nil;

           

            //[self initNetworkCommunication];

            

break;

default:

NSLog(@"Unknown event");

}

}