struct sockaddr_in server_addr;
 server_addr.sin_len = sizeof(struct sockaddr_in);
 server_addr.sin_family = AF_INET;//AF_INET互联网地址簇
 server_addr.sin_port = htons(port);
 server_addr.sin_addr.s_addr = inet_addr(address);
 bzero(&server_addr.sin_zero, 8);
 //创建socket
 int server_socket = socket(AF_INET, SOCK_STREAM, 0);//SOCK_STREAM 有链接
 if (server_socket == -1) {
  perror("socket error!");
  return 1;
 }

 int bind_result = bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr));
 if (bind_result == -1) {
  perror("bind error!");

  return 1;
 }

 if (listen(server_socket, 5)) {
  perror("listen error!");
  return 1;
 }

int client_socket;
 socklen_t address_len;
 struct sockaddr_in client_address;
 for (; ; ) {
  address_len = sizeof(client_address);
  client_socket = accept(server_socket, (struct sockaddr*)&client_address, &address_len);
  //1.使用多线程
  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
   //这个函数进行数据操作
   str_echo(client_socket);
  });
 }

 char buf[1024];
 while (1) {
  bzero(buf, 1024);
  long byte_num = recv(socket, buf, 1024, 0);
  if (byte_num < 0) {
   return;
  }
  buf[byte_num] = '\0';
  printf("client said:%s\n", buf);
  char *result;
  NSString *str = [NSString stringWithCString:buf encoding:NSUTF8StringEncoding];
  if ([str isEqualToString:@"1"]) {
   result = "你猜！";
  }
  else if ([str isEqualToString:@"2"])
  {
   result = "谢谢！";
  }
  else if ([str isEqualToString:@"3"])
  {
   result = "对不起！";
  }
  else if ([str isEqualToString:@"4"])
  {
   result = "好的！";
  }
  else
  {
   if (arc4random()%2 == 0) {
    result = "不知道你在说什么！";
   }
   else
   {
    result = buf;
   }
  }
  send(socket, result, 1024, 0);
 }

struct sockaddr_in server_addr;
 server_addr.sin_len = sizeof(struct sockaddr_in);
 server_addr.sin_family = AF_INET;
 server_addr.sin_port = htons(11332);
 server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
 bzero(&(server_addr.sin_zero), 8);
 int server_socket = socket(AF_INET, SOCK_STREAM, 0);
 if (server_socket == -1) {
  perror("socket error");
  return 1;
 }
 char receive_msg[1024];
 char reply_msg[1024];
 if (connect(server_socket, (struct sockaddr*)&server_addr, sizeof(struct sockaddr_in)) == 0) {
  //connect 成功之后，其实系统将你创建的socket绑定到一个系统分配的端口上，且其为全相关，包含服务器端的信息，可以用来和服务器端进行通信。
  while (1) {
   bzero(reply_msg, 1024);
   printf("replay:");
   scanf("%s", reply_msg);
   if (send(server_socket, reply_msg, 1024, 0) == -1) {
    perror("send error!");
    return 1;
   }
   bzero(receive_msg, 1024);
   long byte_num = recv(server_socket, receive_msg, 1024, 0);
   receive_msg[byte_num] = '\0';
   printf("server said:%s\n", receive_msg);
  }
 }
 return 0;

- (void)viewDidLoad {
 [super viewDidLoad];
 NSString *documentStr = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
 NSString *dataPath = [documentStr stringByAppendingPathComponent:@"data.txt"];
 NSFileManager *manager = [NSFileManager defaultManager];
 if ([manager fileExistsAtPath:dataPath]) {
  self.read = YES;
  NSLog(@"string:%@", [NSString stringWithContentsOfFile:dataPath encoding:NSUTF8StringEncoding error:nil]);
  NSInputStream *inStream = [[NSInputStream alloc] initWithFileAtPath:dataPath];
  [inStream setDelegate:self];
  [inStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
  [inStream open];
 }
 else
 {
  if ([manager createFileAtPath:dataPath contents:nil attributes:nil]) {
   self.read = NO;
   NSOutputStream *outStream = [[NSOutputStream alloc] initToFileAtPath:dataPath append:YES];
   [outStream setDelegate:self];
   [outStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
   [outStream open];
  }
  else
  {
   NSLog(@"文件创建失败！");
  }
 }
}
#pragma mark - <NSStreamDelegate>代理方法
- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode
{
 if (self.read) {
  NSInputStream *inStream = (NSInputStream *)aStream;
  switch (eventCode) {
   case NSStreamEventHasBytesAvailable:
   {
    uint8_t data[1024];
    [inStream read:data maxLength:1024];
    printf("%s", data);
    [inStream close];
    [inStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    inStream = nil;
   }
    break;
   case NSStreamEventEndEncountered:
   {
    [inStream close];
    [inStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    inStream = nil;
   }
    break;
   default:
    break;
  }
 }
 else{
  NSOutputStream *outStream = (NSOutputStream *)aStream;
  switch (eventCode) {
   case NSStreamEventHasSpaceAvailable:
   {
    uint8_t data[] = "{name:'张三', age:10}";
    [outStream write:data maxLength:strlen((char *)data)];
    [outStream close];
    [outStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    outStream = nil;
   }
    break;
   case NSStreamEventEndEncountered:
   {
    [outStream close];
    [outStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    outStream = nil;
   }
    break;
   default:
    break;
  }
 }
}

- (void)viewDidLoad {
 [super viewDidLoad];
 [self startSocket:@"127.0.0.1" andPort:11332];
}
- (void)startSocket:(NSString *)address andPort:(int)port
{
 CFReadStreamRef readRef;
 CFWriteStreamRef writeRef;
 CFStreamCreatePairWithSocketToHost(NULL, (__bridge CFStringRef)address, port, &readRef, &writeRef);
 NSInputStream *inputStream = (__bridge NSInputStream *)readRef;
 NSOutputStream *outputStream = (__bridge NSOutputStream *)writeRef;
 inputStream.delegate = self;
 outputStream.delegate = self;
 [inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
 [outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
 [inputStream open];
 [outputStream open];
 self.outputStream = outputStream;
}
- (IBAction)sendMsg:(UIButton *)sender {
 if (sender.currentTitle > 0) {
  const char *output = sender.currentTitle.UTF8String;
  [self.outputStream write:(const uint8_t *)output maxLength:strlen(output)];
 }
}
- (void)showMessage:(NSString *)msg
{
 if (!self.msgLabel) {
  UIFont *font = [UIFont systemFontOfSize:14];
  UIColor *color = [UIColor blackColor];
  UIColor *backColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0.2];
  UILabel *label = [[UILabel alloc] init];
  label.textColor = color;
  label.font = font;
  label.textAlignment = NSTextAlignmentCenter;
  label.backgroundColor = backColor;
  self.msgLabel = label;
 }
 CGFloat screenW = [UIScreen mainScreen].bounds.size.width;
 CGFloat screenH = [UIScreen mainScreen].bounds.size.height;
 CGFloat W = screenW - 16;
 CGSize size = [msg boundingRectWithSize:CGSizeMake(W, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:self.msgLabel.font} context:nil].size;
 W = size.width;
 CGFloat H = size.height;
 CGFloat X = (screenW - W)/2;
 CGFloat Y = (screenH - H)/2;
 self.msgLabel.frame = CGRectMake(X, Y, W, H);
 self.msgLabel.text = msg;
 [self.view addSubview:self.msgLabel];
 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
  [self.msgLabel removeFromSuperview];
 });
}
#pragma mark - <NSStreamDelegate>代理方法
- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode
{
 switch (eventCode) {
  case NSStreamEventNone:
   break;
  case NSStreamEventOpenCompleted:
   break;
  case NSStreamEventHasBytesAvailable:
  {
   uint8_t buf[1024];
   NSInteger len = 0;
   NSInputStream *inputStream = (NSInputStream *)aStream;
   len = [inputStream read:buf maxLength:1024];
   if (len) {
    [self showMessage:[NSString stringWithCString:(const char *)buf encoding:NSUTF8StringEncoding]];
   }
   break;
  }
  case NSStreamEventHasSpaceAvailable:
   break;
  case NSStreamEventErrorOccurred:
  {
   [aStream close];
   break;
  }
  case NSStreamEventEndEncountered:
  {
   [aStream close];
   [aStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
   aStream = nil;
   break;
  }
  default:
   break;
 }