ExecutorService实现获取线程返回值

package thread;

import java.util.concurrent.Callable;

/**
 *  一个包含返回值的线程类
 * @author xiezd 2018-01-14 21:40
 *
 */
public class ThreadWithCallback implements Callable{
    private int number;
    public ThreadWithCallback(int number){
        this.number = number;
    }
    //相当于Thread的run方法
    @Override
    public Object call() throws Exception {
        long begin = System.currentTimeMillis();
        int index = (int)(Math.random() * 99999999);
        int result = number;
        //随便写的
        for (int i = 1; i < index; i++) {
            result = (result / i ) * index;
        }
        long end = System.currentTimeMillis();
        return "计算数值为" + number + "的线程，花费：" + (end - begin) + "毫秒。";
    }
}

package thread;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/**
 * @author xiezd 2018-01-14 21:49
 */
public class App {
    public static void main(String[] args) {
        ExecutorService executors = Executors.newFixedThreadPool(10);
        try {
            /* 启动线程时会返回一个Future对象。
             * 可以通过future对象获取现成的返回值。
             * 在执行future.get()时，主线程会堵塞，直至当前future线程返回结果。
             */
            Future future1 = executors.submit(new ThreadWithCallback(20));
            Future future2 = executors.submit(new ThreadWithCallback(30));
            System.out.println(future1.get());
            System.out.println(future2.get());

        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }finally {
            executors.shutdown();
        }
    }
}