- (void)groupEvent{

    //创建线程

    dispatch_group_t group =dispatch_group_create();

    dispatch_queue_t globalQueue=dispatch_get_global_queue(, );

    dispatch_group_enter(group);

    //模拟多线程耗时操作

    dispatch_group_async(group, globalQueue, ^{

        sleep();

        NSLog(@"%@---block1结束。。。",[NSThread currentThread]);

        dispatch_group_leave(group);

    });

    NSLog(@"%@---1NSLOG结束。。。",[NSThread currentThread]);

    dispatch_group_enter(group);

    //模拟多线程耗时操作

    dispatch_group_async(group, globalQueue, ^{

        sleep();

        NSLog(@"%@---block2结束。。。",[NSThread currentThread]);

        dispatch_group_leave(group);

    });

    NSLog(@"%@---2NSLOG结束。。。",[NSThread currentThread]);

    //线程全部结束

    dispatch_group_notify(group, dispatch_get_global_queue(, ), ^{

        NSLog(@"%@---全部结束。。。",[NSThread currentThread]);

    });

}

-- ::27.853 CPMNetworking[:] <NSThread: 0x600000068600>{number = , name = main}---1NSLOG结束。。。

-- ::27.856 CPMNetworking[:] <NSThread: 0x600000068600>{number = , name = main}---2NSLOG结束。。。

-- ::30.923 CPMNetworking[:] <NSThread: 0x608000263f00>{number = , name = (null)}---block1结束。。。

-- ::30.930 CPMNetworking[:] <NSThread: 0x6000002647c0>{number = , name = (null)}---block2结束。。。

-- ::30.930 CPMNetworking[:] <NSThread: 0x6000002647c0>{number = , name = (null)}---全部结束。。。