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iOS GCD多线程

2018-12-04 21:51 出处:清屏网 人气: 评论(0

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}
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