java的线程计数器实现抢购的小测试

秒速五厘米 2022-05-30 04:22 204阅读 0赞

一个使用线程计数器来实现的小功能，没有适用场景，没有实践过。希望有经验的大神，能够帮忙纠正。

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一个恶汉单例类来限定程序对应用的创建：

public class SingleHelp {
    
        private SingleHelp() {}
        private static final  SingleHelp instance = new SingleHelp();
        private static int HEAD_NUM = 10;
        private static CountDownLatch cd = new CountDownLatch(12);
        public static SingleHelp getInstance() {
            if (HEAD_NUM == 0) {
                try {
                    cd.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                return null;
            }else {
                System.out.println("取了一个出来，还剩下："+(HEAD_NUM--));
                cd.countDown();
            }
            return instance;
        }
    
    }

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模拟多个人点击操作：

public class TestSingHelp {
        public static void main(String[] args) {
            Thread t = null;
            for (int i = 0; i < 50; i++) {
                try {
                    t = new Thread(new Runnable() {
                        @Override
                        public void run() {
                            SingleHelp s = SingleHelp.getInstance();
                            System.out.println("当前第"+Thread.currentThread().getName()+"线程");
                            if (s == null) {
                                Thread.currentThread().interrupt();
                                throw new RuntimeException("抢完了");
                            }
                        }
                    },"thread"+i);
                    t.start();
                } catch (Exception e) {
                    e.printStackTrace();
                    break;
                }
            }
    
        }
    
    }

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运行结果：

![这里写图片描述][70]

[70]: /images/20220530/3d80532267d04afcb1926c11e672ed98.png