成都做seo网站公司/技能培训机构排名前十

用线程代表不同售票窗口，用线程执行的方法模拟售票。如果不加锁，会出现多个售票窗口同时售一张票的情况。

@property (nonatomic, strong) NSThread *thread1;
@property (nonatomic, strong) NSThread *thread2;
@property (nonatomic, strong) NSThread *thread3;/***  剩余票数*/
@property (nonatomic, assign) int leftTicketCount;

self.leftTicketCount = 50;self.thread1 = [[NSThread alloc] initWithTarget:self selector:@selector(saleTicket) object:nil];self.thread1.name = @"1号窗口";self.thread2 = [[NSThread alloc] initWithTarget:self selector:@selector(saleTicket) object:nil];self.thread2.name = @"2号窗口";self.thread3 = [[NSThread alloc] initWithTarget:self selector:@selector(saleTicket) object:nil];self.thread3.name = @"3号窗口";

//开售
    [self.thread1 start];[self.thread2 start];[self.thread3 start];

/***  卖票 加锁了就不会出现线程安全问题
 *  不加锁就会出问题*/
- (void)saleTicket
{while (1) {// ()小括号里面放的是锁对象@synchronized(self) { // 开始加锁int count = self.leftTicketCount;if (count > 0) {[NSThread sleepForTimeInterval:0.05];//睡一会，为了让不同线程抢夺统一资源问题更加明显
                self.leftTicketCount = count - 1;NSLog(@"%@卖了一张票, 剩余%d张票", [NSThread currentThread].name, self.leftTicketCount);} else {return; // 退出循环
            }} // 解锁
    }
}

另外，加锁是消耗CPU资源的，尽量将加锁，资源抢夺的业务逻辑交给服务器端处理，减小移动端的压力。

参考来自：黑马iOS-MJ教程视频