FutureTask demo

package com.xinwei.order.entity;

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

public class CallableTest {  

    public static void main(String[] args) {
        //创建线程池
        ExecutorService es = Executors.newSingleThreadExecutor();
        //创建Callable对象任务
        CallableDemo calTask=new CallableDemo();
        //提交任务并获取执行结果
        Future<Integer> future =es.submit(calTask);
        //关闭线程池
        es.shutdown();
        try {
            Thread.sleep(2000);
        System.out.println("主线程在执行其他任务");  

        if(future.get()!=null){
            //输出获取到的结果
            System.out.println("future.get()-->"+future.get());
        }else{
            //输出获取到的结果
            System.out.println("future.get()未获取到结果");
        }  

        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("主线程在执行完成");
    }
}

package com.xinwei.order.entity;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;

public class eeeee {  

    public static void main(String[] args) {
        //创建线程池
        ExecutorService es = Executors.newSingleThreadExecutor();
        //创建Callable对象任务
        CallableDemo calTask=new CallableDemo();
        //创建FutureTask
        FutureTask<Integer> futureTask=new FutureTask<>(calTask);
        //执行任务
        es.submit(futureTask);
        //关闭线程池
        es.shutdown();
        try {
            Thread.sleep();
        System.out.println("主线程在执行其他任务");  

        if(futureTask.get()!=null){
            //输出获取到的结果
            System.out.println("futureTask.get()-->"+futureTask.get());
        }else{
            //输出获取到的结果
            System.out.println("futureTask.get()未获取到结果");
        }  

        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("主线程在执行完成");
    }
} 

import java.util.concurrent.Callable;  

public class CallableDemo implements Callable<Integer> {  

    private int sum;
    @Override
    public Integer call() throws Exception {
        System.out.println("Callable子线程开始计算啦！");
        Thread.sleep();  

        for(int i= ;i<;i++){
            sum=sum+i;
        }
        System.out.println("Callable子线程计算结束！");
        return sum;
    }
}