线程池-callable任务

1 带回调的线程池任务

Callable接口和Runable接口最大的区别是Callable可以拥有返回值，并可以通过回调的方式获取。同时通过Future的get方法，可以同步的获取到返回值，并保证任务已经完成

package com.cweeyii.threadpool;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;

/**
 * Created by wenyi on 16/10/16.
 * Email:[email protected]
 */
public class CallableThreadPool {
    private static final Logger LOGGER = LoggerFactory.getLogger(CallableThreadPool.class);

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        int threadSize = 2;
        ExecutorService executorService = Executors.newFixedThreadPool(threadSize);
        List> futureList=new ArrayList<>();
        for (int i = 0; i < threadSize * 2; i++) {
            CallableWorker worker = new CallableWorker();
            Future future = executorService.submit(worker);
            futureList.add(future);
        }
        executorService.shutdown();
        for(Future future:futureList){
            CallerHandle callerHandle=future.get();
            LOGGER.info("{} 已经完成任务",callerHandle.getThreadName());
        }
        LOGGER.info("线程池关闭成功");
    }
}

14:26:37.574  INFO (CallableWorker.java:20) - pool-1-thread-1 结束任务
14:26:37.575  INFO (CallableWorker.java:20) - pool-1-thread-2 结束任务
14:26:37.579  INFO (CallableThreadPool.java:29) - pool-1-thread-1 已经完成任务
14:26:37.582  INFO (CallableThreadPool.java:29) - pool-1-thread-2 已经完成任务
14:26:39.583  INFO (CallableWorker.java:20) - pool-1-thread-1 结束任务
14:26:39.583  INFO (CallableWorker.java:20) - pool-1-thread-2 结束任务
14:26:39.583  INFO (CallableThreadPool.java:29) - pool-1-thread-1 已经完成任务
14:26:39.584  INFO (CallableThreadPool.java:29) - pool-1-thread-2 已经完成任务
14:26:39.584  INFO (CallableThreadPool.java:32) - 线程池关闭成功

ps：注意必须调用线程池的shutdown方法，否则JVM虚拟机不会结束。同理子线程如果为非守护线程，JVM也必须等待所有线程结束后才能结束。

示例1：菲守护线程

package com.cweeyii.threadpool;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Created by wenyi on 16/10/16.
 * Email:[email protected]
 */
public class MainExit {
    private static final Logger LOGGER = LoggerFactory.getLogger(MainExit.class);

    public static void main(String[] args) {
        new Thread(new SleepWorker()).start();
        new Thread(new SleepWorker()).start();
        LOGGER.info("主线程main已经完成={}",Thread.currentThread().getName());
    }
}

15:57:06.639  INFO (MainExit.java:16) - 主线程main已经完成=main
15:57:08.641  INFO (SleepWorker.java:31) - threadName=Thread-1 线程结束null工作
15:57:08.641  INFO (SleepWorker.java:31) - threadName=Thread-0 线程结束null工作

示例2：守护线程

public class MainExit {
    private static final Logger LOGGER = LoggerFactory.getLogger(MainExit.class);

    public static void main(String[] args) {
        Thread thread1=new Thread(new SleepWorker());
        Thread thread2=new Thread(new SleepWorker());
        thread1.setDaemon(true);
        thread2.setDaemon(true);
        LOGGER.info("主线程main已经完成={}",Thread.currentThread().getName());
    }
}

15:58:00.128  INFO (MainExit.java:18) - 主线程main已经完成=main