直接上代码 --> 各种线程的创建方式
- /// 创建异步队列
- dispatch_queue_t async = dispatch_queue_create("async_queue", DISPATCH_QUEUE_CONCURRENT);
- /// 创建同步队列
- dispatch_queue_t sync = dispatch_queue_create("sync_queue", DISPATCH_QUEUE_SERIAL);
- /// 创建主队列
- dispatch_queue_t main_queue = dispatch_get_main_queue();
- /// 全局并发队列
- dispatch_queue_t global_queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
- /// 同步
- dispatch_sync(global_queue, ^{
- });
- /// 异步
- dispatch_async(global_queue, ^{
- });
线程创建的 6 中方式
第一种 --> 同步并发 (从上往下依次执行, 没有开启新线程) 在当前线程中执行任务, 不会开启新线程, 执行完一个任务, 再执行下一个任务
| 执行结果 --> 添加至主线程执行先执行 begin 最后执行 end, 依次执行
- - (void)syncConcurrentThread
- {
- NSLog(@"同步并发 ---begin %@",[NSThread currentThread]);
- dispatch_queue_t sync = dispatch_queue_create("syncConcurrent", DISPATCH_QUEUE_CONCURRENT);
- dispatch_sync(sync, ^{
- for (int i = 0; i <3; i++) {
- NSLog(@"syncConcurrent = 1--%@",[NSThread currentThread]);
- }
- });
- dispatch_sync(sync, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"syncConcurrent = 2--%@",[NSThread currentThread]);
- }
- });
- dispatch_sync(sync, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"syncConcurrent = 3--%@",[NSThread currentThread]);
- }
- });
- NSLog(@"同步并发 ---end %@",[NSThread currentThread]);
- }
执行结果:
同步并发 ---begin <NSThread: 0x600000566940>{number = 1, name = main}
- syncConcurrent = 1--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncConcurrent = 1--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncConcurrent = 1--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncConcurrent = 2--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncConcurrent = 2--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncConcurrent = 2--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncConcurrent = 3--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncConcurrent = 3--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncConcurrent = 3--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
同步并发 ---end <NSThread: 0x600000566940>{number = 1, name = main}
第二种 --> 异步并发 (开启多个新线程, 任务随机接近同时执行) 可以开启多个线程, 任务同时随机执行
| 执行结果 --> 先执行主线程代码 (begin,end), 在执行子线程代码, 并随机执行
- - (void)asyncConcurrentThread
- {
- NSLog(@"异步并发 ---begin %@",[NSThread currentThread]);
- dispatch_queue_t sync = dispatch_queue_create("syncConcurrent", DISPATCH_QUEUE_CONCURRENT);
- dispatch_async(sync, ^{
- for (int i = 0; i <3; i++) {
- NSLog(@"asyncConcurrent = 1--%@",[NSThread currentThread]);
- }
- });
- dispatch_async(sync, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"asyncConcurrent = 2--%@",[NSThread currentThread]);
- }
- });
- dispatch_async(sync, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"asyncConcurrent = 3--%@",[NSThread currentThread]);
- }
- });
- NSLog(@"异步并发 ---end %@",[NSThread currentThread]);
- }
执行结果:
异步并发 ---begin <NSThread: 0x600000566940>{number = 1, name = main}
异步并发 ---end <NSThread: 0x600000566940>{number = 1, name = main}
- asyncConcurrent = 1--<NSThread: 0x600000538980>{
- number = 3, name = (null)
- }
- asyncConcurrent = 3--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncConcurrent = 2--<NSThread: 0x60000050ad40>{
- number = 5, name = (null)
- }
- asyncConcurrent = 1--<NSThread: 0x600000538980>{
- number = 3, name = (null)
- }
- asyncConcurrent = 3--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncConcurrent = 2--<NSThread: 0x60000050ad40>{
- number = 5, name = (null)
- }
- asyncConcurrent = 1--<NSThread: 0x600000538980>{
- number = 3, name = (null)
- }
- asyncConcurrent = 3--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncConcurrent = 2--<NSThread: 0x60000050ad40>{
- number = 5, name = (null)
- }
第三种 --> 同步串行 (任务依次执行, 没有开启新线程) 不会开启新线程, 在当前线程执行任务. 任务是串行的, 执行完一个任务, 再执行下一个任务
| 执行结果 --> 先执行主线程的代码 (begin,end), 在加入主线程依次执行
- - (void)syncSerialThread
- {
- NSLog(@"同步串行 ---begin %@",[NSThread currentThread]);
- dispatch_queue_t sync = dispatch_queue_create("syncConcurrent", DISPATCH_QUEUE_SERIAL);
- dispatch_sync(sync, ^{
- for (int i = 0; i <3; i++) {
- NSLog(@"syncSerial = 1--%@",[NSThread currentThread]);
- }
- });
- dispatch_sync(sync, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"syncSerial = 2--%@",[NSThread currentThread]);
- }
- });
- dispatch_sync(sync, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"syncSerial = 3--%@",[NSThread currentThread]);
- }
- });
- NSLog(@"同步串行 ---end %@",[NSThread currentThread]);
- }
执行结果:
同步串行 ---begin <NSThread: 0x600000566940>{number = 1, name = main}
- syncSerial = 1--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncSerial = 1--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncSerial = 1--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncSerial = 2--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncSerial = 2--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncSerial = 2--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncSerial = 3--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncSerial = 3--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
- syncSerial = 3--<NSThread: 0x600000566940>{
- number = 1, name = main
- }
同步串行 ---end <NSThread: 0x600000566940>{number = 1, name = main}
第四种 --> 异步串行 (开启一个线程) 会开启新线程, 但是因为任务是串行的, 执行完一个任务, 再执行下一个任务
| 执行结果 --> 先执行主线程 (begin,end), 然后在新的线程依次执行任务
- - (void)asyncSerialThread
- {
- NSLog(@"异步串行 ---begin %@",[NSThread currentThread]);
- dispatch_queue_t sync = dispatch_queue_create("syncConcurrent", DISPATCH_QUEUE_SERIAL);
- dispatch_async(sync, ^{
- for (int i = 0; i <3; i++) {
- NSLog(@"asyncSerial = 1--%@",[NSThread currentThread]);
- }
- });
- dispatch_async(sync, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"asyncSerial = 2--%@",[NSThread currentThread]);
- }
- });
- dispatch_async(sync, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"asyncSerial = 3--%@",[NSThread currentThread]);
- }
- });
- NSLog(@"异步串行 ---end %@",[NSThread currentThread]);
- }
执行结果:
异步串行 ---begin <NSThread: 0x600000566940>{number = 1, name = main}
异步串行 ---end <NSThread: 0x600000566940>{number = 1, name = main}
- asyncSerial = 1--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncSerial = 1--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncSerial = 1--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncSerial = 2--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncSerial = 2--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncSerial = 2--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncSerial = 3--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncSerial = 3--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
- asyncSerial = 3--<NSThread: 0x600000538880>{
- number = 4, name = (null)
- }
第五种 --> 同步执行 + 主队列 在主线程调用 (卡死) 在其他线程调用 (不会卡死, 不会开启新线程, 依次执行)
| 执行结果 --> 在主队列执行 (卡死) 在子线程中 (依次执行)
- - (void)syncMainThread
- {
- NSLog(@"同步执行 + 主队列 ---begin %@",[NSThread currentThread]);
- dispatch_queue_t main_queue = dispatch_get_main_queue();
- dispatch_sync(main_queue, ^{
- for (int i = 0; i <3; i++) {
- NSLog(@"syncMain = 1--%@",[NSThread currentThread]);
- }
- });
- dispatch_sync(main_queue, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"syncMain = 2--%@",[NSThread currentThread]);
- }
- });
- dispatch_sync(main_queue, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"syncMain = 3--%@",[NSThread currentThread]);
- }
- });
- NSLog(@"同步执行 + 主队列 ---end %@",[NSThread currentThread]);
- }
执行结果:
---begin <NSThread: 0x6000011b6940>{number = 1, name = main}
第六种 --> 异步执行 + 主队列 在主线程中依次执行
| 执行结果 --> 先执行主线 (begin,end), 然后依次执行任务
- - (void)asyncMainThread
- {
- NSLog(@"异步执行 + 主队列 ---begin %@",[NSThread currentThread]);
- dispatch_queue_t main_queue = dispatch_get_main_queue();
- dispatch_async(main_queue, ^{
- for (int i = 0; i <3; i++) {
- NSLog(@"asyncMain = 1--%@",[NSThread currentThread]);
- }
- });
- dispatch_async(main_queue, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"asyncMain = 2--%@",[NSThread currentThread]);
- }
- });
- dispatch_async(main_queue, ^{
- for (int i = 0; i < 3; i++) {
- NSLog(@"asyncMain = 3--%@",[NSThread currentThread]);
- }
- });
- NSLog(@"异步执行 + 主队列 ---end %@",[NSThread currentThread]);
- }
执行结果:
异步执行 + 主队列 ---begin <NSThread: 0x6000018f6980>{number = 1, name = main}
异步执行 + 主队列 ---end <NSThread: 0x6000018f6980>{number = 1, name = main}
- asyncMain = 1--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
- asyncMain = 1--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
- asyncMain = 1--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
- asyncMain = 2--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
- asyncMain = 2--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
- asyncMain = 2--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
- asyncMain = 3--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
- asyncMain = 3--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
- asyncMain = 3--<NSThread: 0x6000018f6980>{
- number = 1, name = main
- }
来源: http://www.jianshu.com/p/f88d76120624