客户端：
#import "ViewController.h"
#import "GCDAsyncSocket.h"@interface ViewController ()
@property (weak, nonatomic) IBOutlet UITextField *ipField;
@property (weak, nonatomic) IBOutlet UITextField *portField;
@property (weak, nonatomic) IBOutlet UITextField *sendMsgField;
@property (weak, nonatomic) IBOutlet UITextView *reciveMsgTextView;//客户端socket
@property (nonatomic) GCDAsyncSocket *clientSocket;@end@implementation ViewController- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.//1、初始化
self.ipField.text = @"172.16.1.6";
self.clientSocket = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_main_queue()];
}- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}- (IBAction)linkButtonAction:(id)sender {
//连接服务器
[self.clientSocket connectToHost:self.ipField.text onPort:self.portField.text.integerValue withTimeout:-1 error:nil];
}
- (IBAction)sendMsgButtonAction:(id)sender {
NSData *data = [self.sendMsgField.text dataUsingEncoding:NSUTF8StringEncoding];
//withTimeout -1 :无穷大
//tag： 消息标记
[self.clientSocket writeData:data withTimeout:-1 tag:0];
}- (void)showMessageWithText:(NSString *)text {
self.reciveMsgTextView.text = [self.reciveMsgTextView.text stringByAppendingFormat:@"%@\n", text];
}#pragma mark - GCDAsynSocket Delegate
- (void)socket:(GCDAsyncSocket *)sock didConnectToHost:(NSString *)host port:(uint16_t)port{
[self showMessageWithText:@"链接成功"];
[self showMessageWithText:[NSString stringWithFormat:@"服务器IP ： %@", host]];
[self.clientSocket readDataWithTimeout:-1 tag:0];
}//收到消息
- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{
NSString *text = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
[self showMessageWithText:text];
[self.clientSocket readDataWithTimeout:-1 tag:0];
}- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
[self.view endEditing:YES];
}@end

服务端：
#import "ViewController.h"
#import "GCDAsyncSocket.h"@interface ViewController ()<GCDAsyncSocketDelegate>/** 端口号 **/
@property (weak, nonatomic) IBOutlet UITextField *portField;/** 发送消息 **/
@property (weak, nonatomic) IBOutlet UITextField *sendMsgField;/** 连接端口号按钮 **/
@property (weak, nonatomic) IBOutlet UIButton *linkPortButton;/** 发送消息按钮 **/
@property (weak, nonatomic) IBOutlet UIButton *sendMsgButton;/** 接受消息 **/
@property (weak, nonatomic) IBOutlet UITextView *reciveMsgTextView;//服务器socket（开放端口，监听客户端socket的链接）
@property (nonatomic) GCDAsyncSocket *serverSocket;//保护客户端socket
@property (nonatomic) GCDAsyncSocket *clientSocket;@end@implementation ViewController- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.//初始化服务器socket
self.serverSocket = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_main_queue()];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.}/** 连接端口 **/
- (IBAction)linkPortButtonAction:(id)sender {
NSError *error = nil;
BOOL result = [self.serverSocket acceptOnPort:self.portField.text.integerValue error:&error];
if (result && error == nil) {
//开放成功
[self showMessageWithText:@"连接成功"];
}
}/** 发消息 **/
- (IBAction)sendMsgButtonAction:(id)sender {
NSData *data = [self.sendMsgField.text dataUsingEncoding:NSUTF8StringEncoding];
//withTimeout -1: 一直等
//tag:消息标记
[self.clientSocket writeData:data withTimeout:-1 tag:0];
}- (void)showMessageWithText:(NSString *)text {
self.reciveMsgTextView.text = [self.reciveMsgTextView.text stringByAppendingFormat:@"%@\n",text];
}#pragma mark - 服务器socket Delegate
- (void)socket:(GCDAsyncSocket *)sock didAcceptNewSocket:(GCDAsyncSocket *)newSocket{
//保存客户端的socket
self.clientSocket = newSocket;
[self showMessageWithText:@"链接成功"];[self showMessageWithText:[NSString stringWithFormat:@"服务器地址：%@ -端口： %d", newSocket.connectedHost, newSocket.connectedPort]];
[self.clientSocket readDataWithTimeout:-1 tag:0];
}//收到消息
- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{
NSString *text = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
[self showMessageWithText:text];
[self.clientSocket readDataWithTimeout:-1 tag:0];
}@end