//第一种NSThread *t = [[NSThread alloc] initWithTarget:self selector:@selector(mutitly) object:nil];[t start];

       //第二种[NSThread detachNewThreadSelector:@selector(mutitly) toTarget:self withObject:nil];

　　　　 //第三种，这种比较常用[self performSelectorInBackground:@selector(mutitly) withObject:nil];

　　　　//第四种NSOperationQueue *operationQueue = [[NSOperationQueue alloc] init];[operationQueue addOperationWithBlock:^{for (int i = 0 ; i < 20 ; i++) {NSLog(@"多线程 :%d",i);}}];

        //第五种创建线程队列（线程池 ）NSOperationQueue *operationQueue = [[NSOperationQueue alloc] init];//设置线程池中得并发数operationQueue.maxConcurrentOperationCount = 1 ;NSInvocationOperation *invocation1 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(thread1) object:nil];[invocation1 setQueuePriority:NSOperationQueuePriorityVeryLow];NSInvocationOperation *invocation2 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(thread2) object:nil];[invocation2 setQueuePriority:NSOperationQueuePriorityVeryHigh];[operationQueue addOperation:invocation1];[operationQueue addOperation:invocation2];

-(void)setImageWithURL:(NSURL *) url{//加载网络图片的时候应该开启一个线程，不然加载的时候会阻塞[self performSelectorInBackground:@selector(loadData:) withObject:url];//不推荐使用这种方法调用，因为这时候按钮会卡住//[self loadData:url];
}-(void)loadData:(NSURL *) url{@autoreleasepool {NSData *data = [NSData dataWithContentsOfURL:url];UIImage *image = [UIImage imageWithData:data];//在主线程上执行setImage方法[self performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:YES];}
}

    NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];//设置请求方式[request setHTTPMethod:@"GET"];//设置请求时间[request setTimeoutInterval:50];NSURLResponse *respon ;NSError *error = nil;//发送一个同步请求NSData *data = [NSURLConnection sendSynchronousRequest:requestreturningResponse:&respon error:&error];NSInteger statusCode = [respon statusCode];NSLog(@"响应码：%d",statusCode);NSDictionary *headFields = [respon allHeaderFields];NSLog(@"响应头:%@",headFields);NSString *htmlstring = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];NSLog(@"%@",htmlstring);

- (IBAction)asynchAction:(id)sender {NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];//设置请求方式[request setHTTPMethod:@"GET"];//设置请求时间[request setTimeoutInterval:50];//发送异步请求[NSURLConnection connectionWithRequest:request delegate:self];//第二种异步请求方式，用的不是很多
//    NSOperationQueue *operationQueue = [[NSOperationQueue alloc] init];
//
//    [NSURLConnection sendAsynchronousRequest:request queue:operationQueue completionHandler:^(NSURLResponse *respon, NSData *data, NSError *error) {
//        if([NSThread isMultiThreaded]){
//            NSLog(@"是多线程");
//        }
//
//        NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
//        NSLog(@"%@",string);
//
//    }];

//服务器响应的方法- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;NSDictionary *allHeadFields = [httpResponse allHeaderFields];NSLog(@"%@",allHeadFields);
}
//接受数据的方法,会调用多次，每一次调用服务器的一部分数据data
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{[resultData appendData:data];}
//数据加载完成调用的方法
- (void)connectionDidFinishLoading:(NSURLConnection *)connection{NSString *htmlString = [[NSString alloc] initWithData:resultData encoding:NSUTF8StringEncoding];NSLog(@"%@",htmlString);}

-(void)mutiThread{//多线程里面开启一个定时器可以提高精确度//启动定时器NSLog(@"定时器启动");@autoreleasepool {[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerAction:) userInfo:nil repeats:YES];}//获取当前的runloop,线程就停在这里[[NSRunLoop currentRunLoop] run];NSLog(@"after");
}-(void)timerAction:(NSTimer *) timer
{index++;NSLog(@"定时器打印");if (index == 5) {[timer invalidate];}
}