Java：Callable

1、具体实现

1. 创建 FutureTask 辅助类 MyCallable 实现 Callable 接口。
2. 创建 MyCallable 对象：MyCallable myCallable = new MyCallable()。
3. 创建 线程辅助类 FutureTask 对象：FutureTask futureTask = new FutureTask(myCallable)。
4. 创建线程对象：Thread thread1 = new Thread(futureTask, “线程一”)。
5. 调用线程对象的 start() 方法。

public class CallableDemo {
    
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        MyCallable myCallable = new MyCallable();
        FutureTask<Integer> futureTask = new FutureTask(myCallable);
        FutureTask<Integer> futureTask2 = new FutureTask(myCallable);
        Thread thread1 = new Thread(futureTask, "线程一");
        Thread thread2 = new Thread(futureTask2, "线程二");
        thread1.start();
        thread2.start();

        Integer integer1 = futureTask.get();
        Integer integer2 = futureTask2.get();
        System.out.println("最后剩余票数为:" + integer1 + "," + integer2);
    }

    static class MyCallable implements Callable<Integer> {

        // 100 张票
        private static int ticket = 100;

        @Override
        public Integer call() throws Exception {

            while (ticket > 1) {
                ticket--;
                System.out.println(Thread.currentThread() + "卖掉了1张票，剩余票数为:" + ticket);

                Thread.sleep(200L);
            }

            return ticket;
        }
    }
}

线程实现	特点
继承 Thread	单继承，无返回值
实现 Runnable	可以多实现，无返回值
实现 Callable	可以多实现，有返回值