执行器中执行任务并返回结果

package cn.itcast.test1;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadPoolExecutor;

//1.创建个类实现Callable接口，接口的泛型参数为String类型

class MyCall implements Callable<String>{

//2,实现call()方法返回String类型

    @Override
    public String call() throws Exception {
        return "this is demo!";
    }
    
}

public class ExecutorsReturn {

   public static void main(String[] args) throws Exception {

//3，通过Executors工厂类的newFixedThreadPool()方法创建ThreadPoolExecutor执行器(我写newSingleThrealPool它总说转化异常 )

ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(3);

//4，创建Callable接口的实例

    MyCall call = new MyCall();

//5，调用执行器的submit()方法发送Callable任务给执行器，这个方法返回一个Future<String>对象管理任务和得到的结果

    Future<String> result = executor.submit(call);

//6，对与每个Future对象来讲，通过调用get()方法将得到由任务返回的String对象

    System.out.println(result.get());
}
}