一、基本概念
在iOS中以NSStream(流)來發(fā)送和接收數(shù)據(jù)，可以設(shè)置流的代理，對(duì)流狀態(tài)的變化做出相應(yīng)。
1連接建立
2接收到數(shù)據(jù)
3連接關(guān)閉
NSStream：數(shù)據(jù)流的父類，用于定義抽象特性，例如：打開、關(guān)閉代理，NSStream繼承自CFStream(CoreFoundation)
NSInputStream：NSStream的子類，用于讀取輸入
NSOutputStream：NSSTream的子類，用于寫輸出

二、開發(fā)步驟
1、網(wǎng)絡(luò)連接設(shè)置
設(shè)置網(wǎng)絡(luò)連接，綁定到主機(jī)和端口
設(shè)置輸入流和輸出流的代理，監(jiān)聽數(shù)據(jù)流的狀態(tài)
將輸入輸出流添加至運(yùn)行循環(huán)
打開輸入流和輸出流
2、發(fā)送消息給服務(wù)器
3、有可讀取字節(jié)時(shí)，讀取服務(wù)器返回的內(nèi)容
4、到達(dá)流末尾時(shí)，關(guān)閉流，同時(shí)并從主運(yùn)行循環(huán)中刪除

#import "ViewController.h"

@interface ViewController ()<NSStreamDelegate>{
    NSInputStream *_inputStream;
    NSOutputStream *_outputSteam;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}


- (IBAction)connectToServer:(id)sender {
    //ios里實(shí)現(xiàn)sokcet的連接，使用C語言
    
    // 1.與服務(wù)器通過三次握手建立連接
    NSString *host = @"127.0.0.1";
    int port = 12345;
    
    // 2.定義輸入輸出流
    CFReadStreamRef readStream;
    CFWriteStreamRef writeStream;
    
    // 3.分配輸入輸出流的內(nèi)存空間
    CFStreamCreatePairWithSocketToHost(NULL, (__bridge CFStringRef)host, port, &readStream, &writeStream);
    
    // 4.把C語言的輸入輸出流轉(zhuǎn)成OC對(duì)象
    _inputStream = (__bridge NSInputStream *)readStream;
    _outputSteam = (__bridge NSOutputStream *)(writeStream);
    
    // 5.設(shè)置代理,監(jiān)聽數(shù)據(jù)接收的狀態(tài)
    _outputSteam.delegate = self;
    _inputStream.delegate = self;
    
    // 把輸入輸入流添加到主運(yùn)行循環(huán)(RunLoop)
    // 主運(yùn)行循環(huán)是監(jiān)聽網(wǎng)絡(luò)狀態(tài)
    [_outputSteam scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
    [_inputStream scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
    
    
    // 6.打開輸入輸出流
    [_inputStream open];
    [_outputSteam open];
}


//代理的回調(diào)是在主線程
//NSLog(@"%@",[NSThread currentThread]);
-(void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode{

//    NSStreamEventOpenCompleted = 1UL << 0,
//    NSStreamEventHasBytesAvailable = 1UL << 1,
//    NSStreamEventHasSpaceAvailable = 1UL << 2,
//    NSStreamEventErrorOccurred = 1UL << 3,
//    NSStreamEventEndEncountered = 1UL << 4
    
    switch (eventCode) {
        case NSStreamEventOpenCompleted:
            NSLog(@"%@",aStream);
            NSLog(@"成功連接建立，形成輸入輸出流的傳輸通道");
            break;
            
        case NSStreamEventHasBytesAvailable:
            NSLog(@"有數(shù)據(jù)可讀");
            [self readData];
            break;
            
        case NSStreamEventHasSpaceAvailable:
            NSLog(@"可以發(fā)送數(shù)據(jù)");
            break;
            
         case NSStreamEventErrorOccurred:
            NSLog(@"有錯(cuò)誤發(fā)生，連接失敗");
            break;
            
         case NSStreamEventEndEncountered:
            NSLog(@"正常的斷開連接");
            //把輸入輸入流關(guān)閉，而還要從主運(yùn)行循環(huán)移除
            [_inputStream close];
            [_outputSteam close];
            [_inputStream removeFromRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
            [_outputSteam removeFromRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

            break;
        default:
            break;
    }

}

- (IBAction)loginBtnClick:(id)sender {
    //發(fā)送登錄請(qǐng)求 使用輸出流
    
    //拼接登錄的指令 iam:zhangsan
    NSString *loginStr = @"iam:zhangsan";
    
    //uint8_t * 字符數(shù)組
    NSData *data = [loginStr dataUsingEncoding:NSUTF8StringEncoding];
    [_outputSteam write:data.bytes maxLength:data.length];
    
}


#pragma mark 讀取服務(wù)器返回的數(shù)據(jù)
-(void)readData{
    
    //定義緩沖區(qū) 這個(gè)緩沖區(qū)只能存儲(chǔ)1024字節(jié)
    uint8_t buf[1024];
    
    // 讀取數(shù)據(jù)
    // len為從服務(wù)器讀取到的實(shí)際字節(jié)數(shù)
    NSInteger len = [_inputStream read:buf maxLength:sizeof(buf)];
    
    // 把緩沖區(qū)里的實(shí)現(xiàn)字節(jié)數(shù)轉(zhuǎn)成字符串
    NSString *receiverStr = [[NSString alloc] initWithBytes:buf length:len encoding:NSUTF8StringEncoding];
    NSLog(@"%@",receiverStr);

}
@end