使用线程池ThreadPoolExecutor调用Callable并接收返回值（用Future接收）

/** MyCallableA 实现Callable接口 **/

package com.product.supermiketho.threaddemo;
import java.util.concurrent.Callable;

public class MyCallableA implements Callable<MyVo> {
    @Override
    public MyVo call() throws Exception {
        Thread.sleep(5000);
        return new MyVo("A001","A结果");
    }
}

/** MyCallableB 实现Callable接口 **/

package com.product.supermiketho.threaddemo;
import java.util.concurrent.Callable;
public class MyCallableB implements Callable<MyVo> {
    @Override
    public MyVo call() throws Exception {
        Thread.sleep(5000);
        return new MyVo("B001","B结果");
    }
}

/** MyCallableC 实现Callable接口 **/

package com.product.supermiketho.threaddemo;
import java.util.concurrent.Callable;

public class MyCallableC implements Callable<MyVo> {

    @Override
    public MyVo call() throws Exception {
        Thread.sleep(5000);
        return new MyVo("C001","c结果");
    }
}

/**测试类 **/

package com.product.supermiketho.threaddemo;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Future;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * 执行入口
 */
public class CallableRun {
    public static void main(String[] args) {
        long start = System.currentTimeMillis();
        List<Future<Integer>> futureTasks = new ArrayList<>();
        /**
         * 参数：
         * corePoolSize–池中要保留的线程数，即使它们处于空闲状态，除非设置了allowCoreThreadTimeOut
         * maximumPoolSize–池中允许的最大线程数
         * keepAliveTime–当线程数大于核心时，这是多余的空闲线程在终止前等待新任务的最长时间。
         * unit–keepAliveTime参数的时间单位
         * workQueue–用于在执行任务之前保存任务的队列。此队列将仅保存execute方法提交的Runnable任务。
         * IllegalArgumentException–如果以下情况之一成立：corePoolSize<0 keepAliveTime<0 maximumPoolSize<=0 maximumPoolSize
        ThreadPoolExecutor pool = new ThreadPoolExecutor(3, 3, 0, TimeUnit.SECONDS, new LinkedBlockingQueue<>());
        try {
            MyCallableA theCallable = new MyCallableA( );
            Future f = pool.submit(theCallable);
            futureTasks.add(f);

            MyCallableB theCallableB = new MyCallableB( );
            Future fB = pool.submit(theCallableB);
            futureTasks.add(fB);

            MyCallableC theCallableC = new MyCallableC( );
            Future fC = pool.submit(theCallableC);
            futureTasks.add(fC);

            System.out.println("线程 " + futureTasks.size());
            for (Future v : futureTasks) {
                MyVo obj = (MyVo) v.get();
                System.out.println( "getCode---"+obj.getCode() + "   getMsg---"+obj.getMsg());
            }
            pool.shutdown();
            long end = System.currentTimeMillis();
            System.out.println("耗时:{} ms" + (end - start));
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

测试结果 ：

线程 3
getCode---A001   getMsg---A结果
getCode---B001   getMsg---B结果
getCode---C001   getMsg---c结果
耗时:{} ms5041

结论：

MyCallableA ，MyCallableB ，MyCallableC 分别sleep了5s，
最后执行总耗时约为5秒，说明各线程已经异步执行（由线程池分配线程），并阻塞收集结果返回。