// downloadDownloadFile *download = [[DownloadFile alloc] init];// 动态创建线程NSThread *downloadThread = [[NSThread alloc] initWithTarget:download selector:@selector(runDownload:) object:@"download1"];[downloadThread start];// 暂停当前线程2秒[NSThread sleepForTimeInterval:2];// 静态方法创建线程[NSThread detachNewThreadSelector:@selector(runDownload:) toTarget:download withObject:@"download2"];// 隐式创建线程ThreadDownload *threadD = [[ThreadDownload alloc] init];[threadD performSelectorInBackground:@selector(run:) withObject:@"download3"];[self performSelectorInBackground:@selector(mainRun:) withObject:@"download4"];

NSOperationQueue *queue = [[NSOperationQueue alloc] init];// 使用NSOperation的子类NSBlokOperationNSBlockOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:^{     NSLog(@"blockOperation--------%@", [NSThread currentThread]);}];blockOperation.completionBlock = ^() {     NSLog(@"blockOperation 执行完毕!");};//    [blockOperation start];//    [[NSOperationQueue mainQueue] addObject:blockOperation];// 使用NSOperation的子类NSInvocationOperationNSInvocationOperation *invocationOperation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(mainRun:) object:@"invocationOperation"];invocationOperation.completionBlock = ^() {    NSLog(@"invocationOperation 执行完毕!");};// 设置依赖关系，前者依赖于后者，当两个operation都放入queue中时，后者先运行于前者[invocationOperation addDependency:blockOperation];// 放入操作队列(NSOperationQueue)中，实现异步多线程操作[queue addOperation:blockOperation];// 暂停queue 2秒后 恢复queue[queue setSuspended:YES];[NSThread sleepForTimeInterval:2.0];[queue setSuspended:NO];[queue addOperation:invocationOperation];

// GCD并行操作 任务并发执行// 并行可不需显示创建，每次都直接调用dispatch_get_global_queue获得queue就行了dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);dispatch_async(concurrentQueue, ^{        NSLog(@"GCD并行异步任务1------%@", [NSThread currentThread]);});dispatch_async(concurrentQueue, ^{        NSLog(@"GCD并行异步任务2------%@", [NSThread currentThread]);});// GCD串行操作 会按照添加的任务顺序，先进先出，前一个任务完成才执行下一个// 串行需要显示创建，可以创建多个串行队列，串行队列也可以并行执行，但决不能随意的大量创建串行队列dispatch_queue_t serialQueue = dispatch_queue_create("our_serial_queue", NULL);dispatch_async(serialQueue, ^{        NSLog(@"GCD串行异步任务1------%@", [NSThread currentThread]);});dispatch_async(serialQueue, ^{        NSLog(@"GCD串行异步任务2------%@", [NSThread currentThread]);});// Dispatch Group的使用 -> 并行执行多个任务，然后等待全部任务完成再回到主线程执行任务[NSThread sleepForTimeInterval:2.0];NSLog(@"******************************************GCD**********************************************");dispatch_async(concurrentQueue, ^{    dispatch_group_t group = dispatch_group_create();                // 往group添加并行异步任务    dispatch_group_async(group, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{            NSLog(@"并发组异步任务1-------%@", [NSThread currentThread]);　　});　　dispatch_group_async(group, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            NSLog(@"并发组异步任务2-------%@", [NSThread currentThread]);　　});            // 等待组中的任务执行完毕,回到主线程执行block回调　　dispatch_group_notify(group, dispatch_get_main_queue(), ^{            NSLog(@"Dispatch Group主线程任务回调!--------%@", [NSThread currentThread]);   });});