??設(shè)計一個競拍搶答程序：要求設(shè)計三個搶答者（三個線程），而后同時發(fā)出搶答指令，搶答成功者給出成功提示，未搶答成功者給出失敗提示。
??對于這個多線程操作，由于里面涉及到數(shù)據(jù)返回問題，最好使用Callable實現(xiàn)。

import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;
public class ThreadDemo {
    public static void main(String[] args) throws Exception {
        MyThread mt = new MyThread();
        FutureTask<String> taskA = new FutureTask(mt);
        FutureTask<String> taskB = new FutureTask(mt);
        FutureTask<String> taskC = new FutureTask(mt);
        new Thread(taskA, "A").start();
        new Thread(taskB, "B").start();
        new Thread(taskC, "C").start();
        System.out.println(taskA.get());
        System.out.println(taskB.get());
        System.out.println(taskC.get());
    }
}
class MyThread implements Callable<String> {
    private boolean flag = false;//搶到處理
    @Override
    public String call() throws Exception {
        synchronized (this) {//數(shù)據(jù)同步
            if (this.flag == false) {//搶答成功
                this.flag = true;
                return Thread.currentThread().getName() + "搶答成功!";
            } else {
                return Thread.currentThread().getName() + "搶答失敗!";
            }
        }
    }
}