Callable、Future和FutureTask区别实践《并发编程》

实现原理

从下图可以看出Runnable 和Callable都是函数式接口（函数式接口(Functional Interface)就是一个有且仅有一个抽象方法,但是可以有多个非抽象方法的接口。），一般使用都结合线程池进行使用。

异步线程的实现（非线池方式）

package com.lys.thread;

import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;

/**
 * @Auther: liuysh
 * @Date: 2021/9/18 15:02
 * @Description:
 */
public class MyFutureTaskTest {
    public static void main(String[] args) throws Exception{

        Callable<Integer> aCallable =()->10;

        Callable<Integer> bCallable =()->20;


        FutureTask<Integer> aFutureTask = new FutureTask<>(aCallable);
        FutureTask<Integer> bFutureTask = new FutureTask<>(bCallable);


        new Thread(aFutureTask).start();
        new Thread(bFutureTask).start();

        Integer a = aFutureTask.get();
        Integer b = bFutureTask.get();


        int c=a+b;
        System.out.println("非线程池异步获取a+b=：" +c);

    }
}

线程池的实现方式

package com.lys.thread;

import java.util.concurrent.*;

/**
 * @Auther: liuysh
 * @Date: 2021/9/18 11:24
 * @Description:
 */
public class ThreadPoolTest {
    public static void main(String[] args) throws Exception {
        System.out.println("当前系统支持核心线程数："+Runtime.getRuntime().availableProcessors());
        ExecutorService executorService= Executors.newFixedThreadPool(2);


        Callable<Integer> aCallable=()->1;
        Callable<Integer> bCallable=()->1;


        Future<Integer> aFuture= executorService.submit(aCallable);
        Future<Integer> bFuture= executorService.submit(bCallable);


        Integer a = aFuture.get();
        Integer b = bFuture.get();


        int c=a+b;


        System.out.println("线程池异步获取a+b=：" +c);
        executorService.shutdown();


    }
}