package com.xz.thread.FutureTask;

import java.util.concurrent.Callable;

/**
 * @description: 創(chuàng)建一個計算任務(wù)類，實現(xiàn)Callable接口,重寫call方法
 * @author: xz
 * @create: 2021-06-02 22:06
 */
public class ComputeTask implements Callable<Integer> {

    private String taskName;//任務(wù)名稱

    //任務(wù)構(gòu)造器
    public ComputeTask(String taskName) {
        this.taskName = taskName;
        System.out.println("創(chuàng)建【計算任務(wù)】開始，計算任務(wù)名稱：" + taskName);
    }

    //計算任務(wù)的方法
    @Override
    public Integer call() throws Exception {
        Integer result = 0;
        for (int i = 1; i <=50; i++) {
            result = +i;
        }
        System.out.println("【計算任務(wù)】"+taskName +"執(zhí)行完成。");
        return result;
    }
}

package com.xz.thread.FutureTask;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;

/**
 * @description:
 * @author: xz
 * @create: 2021-06-01 22:44
 */
public class Demo {
    public static void main(String[] args) {
        //任務(wù)集合
        List<FutureTask<Integer>> futureTasks  = new ArrayList<>();
        //創(chuàng)建固定長度的線程池
        ExecutorService pool = Executors.newFixedThreadPool(5);
        for (int i = 1; i <= 10; i++) {
            //實例化FutureTask，傳入計算任務(wù)類
            FutureTask<Integer> futureTask = new FutureTask<>(new ComputeTask(i + ""));
            //添加到任務(wù)集合中
            futureTasks.add(futureTask);
            //提交任務(wù)到線程池
            pool.submit(futureTask);
        }
        System.out.println("所有【計算任務(wù)】提交完畢，主線程開始執(zhí)行");

        System.out.println("【主線程任務(wù)】開始============");
        //主線程睡眠5秒，模擬主線程做某些任務(wù)
        try {
            Thread.sleep(5000);
            System.out.println("【主線程任務(wù)】開始執(zhí)行某些任務(wù)============");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("【主線程任務(wù)】結(jié)束============");

        //用于打印任務(wù)執(zhí)行結(jié)果
        Integer result = 0;
        for (FutureTask<Integer> task : futureTasks) {
            try {
                //FutureTask的get()方法會自動阻塞，知道得到任務(wù)執(zhí)行結(jié)果為止
                result += task.get();
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (ExecutionException e) {
                e.printStackTrace();
            }
        }
        //關(guān)閉線程池
        pool.shutdown();
        System.out.println("多線程多任務(wù)執(zhí)行結(jié)果：" + result);

    }

}