线程池-shutdownNow

1.shutdownNow

shutdownNow和shutdown的最主要的区别是：shutdown会等待所有提交的任务执行完成，不管是正在执行还是保存在任务队列中的已提交任务。而shutdownNow会尝试中断正在执行的任务（其主要是中断一些指定方法如sleep方法），并且停止执行等待队列中提交的任务。

中断Sleep任务

package com.cweeyii.threadpool;

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

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


    public String getWorkerName() {
        return workerName;
    }

    public void setWorkerName(String workerName) {
        this.workerName = workerName;
    }

    @Override
    public void run() {
        String threadName = Thread.currentThread().getName();
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        LOGGER.info("threadName={} 线程结束{}工作", threadName,workerName);
    }
}

package com.cweeyii.threadpool;

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

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

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

    public static void main(String[] args) throws InterruptedException, ExecutionException, TimeoutException {
        int workerNum = 2;
        ExecutorService executorService = Executors.newFixedThreadPool(workerNum);
        for (int i = 0; i < workerNum*3; i++) {
            SleepWorker worker=new SleepWorker();
            worker.setWorkerName("worker" + i);
            executorService.submit(worker);
        }
        List workerList=executorService.shutdownNow();
        executorService.awaitTermination(10, TimeUnit.SECONDS);
        LOGGER.info("调用shutdown会立即返回不会等待线程池任务执行完");
        for(Runnable woker:workerList){
            FutureTask futureTask=(FutureTask)woker;
            futureTask.run();
        }
    }
}

java.lang.InterruptedException: sleep interrupted
    at java.lang.Thread.sleep(Native Method)
    at com.cweeyii.threadpool.SleepWorker.run(SleepWorker.java:27)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
java.lang.InterruptedException: sleep interrupted
    at java.lang.Thread.sleep(Native Method)
    at com.cweeyii.threadpool.SleepWorker.run(SleepWorker.java:27)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
11:45:17.513  INFO (SleepWorker.java:31) - threadName=pool-1-thread-2 线程结束worker1工作
11:45:17.513  INFO (SleepWorker.java:31) - threadName=pool-1-thread-1 线程结束worker0工作
11:45:17.516  INFO (ShutDownNowSleep.java:26) - 调用shutdown会立即返回不会等待线程池任务执行完
11:45:19.521  INFO (SleepWorker.java:31) - threadName=main 线程结束worker2工作
11:45:21.525  INFO (SleepWorker.java:31) - threadName=main 线程结束worker3工作
11:45:23.526  INFO (SleepWorker.java:31) - threadName=main 线程结束worker4工作
11:45:25.527  INFO (SleepWorker.java:31) - threadName=main 线程结束worker5工作

忽略等待的任务

package com.cweeyii.threadpool;

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

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

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

    public static void main(String[] args) throws InterruptedException, ExecutionException, TimeoutException {
        int workerNum = 2;
        ExecutorService executorService = Executors.newFixedThreadPool(workerNum);
        for (int i = 0; i < workerNum*3; i++) {
            BusyWorker worker=new BusyWorker();
            worker.setWorkerName("worker" + i);
            executorService.submit(worker);
        }
        List workerList=executorService.shutdownNow();
        executorService.awaitTermination(10, TimeUnit.SECONDS);
        LOGGER.info("调用shutdown会立即返回不会等待线程池任务执行完");
        for(Runnable woker:workerList){
            FutureTask futureTask=(FutureTask)woker;
            futureTask.run();
        }
    }
}

package com.cweeyii.threadpool;

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

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

    private String workerName;


    public String getWorkerName() {
        return workerName;
    }

    public void setWorkerName(String workerName) {
        this.workerName = workerName;
    }
    @Override
    public void run() {
        String threadName = Thread.currentThread().getName();
        try {
            busyMethod();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        LOGGER.info("threadName={} 线程结束{}工作", threadName,workerName);
    }

    private void busyMethod() throws InterruptedException{
        int k=0;
        for(long i=0;i<100000L;i++){
            for(long j=0;j<100000L;j++)
                k++;
        }
    }
}

11:47:15.086  INFO (BusyWorker.java:31) - threadName=pool-1-thread-1 线程结束worker0工作
11:47:15.087  INFO (BusyWorker.java:31) - threadName=pool-1-thread-2 线程结束worker1工作
11:47:15.089  INFO (ShutDownNowBusy.java:26) - 调用shutdown会立即返回不会等待线程池任务执行完
11:47:19.354  INFO (BusyWorker.java:31) - threadName=main 线程结束worker2工作
11:47:23.123  INFO (BusyWorker.java:31) - threadName=main 线程结束worker3工作
11:47:26.912  INFO (BusyWorker.java:31) - threadName=main 线程结束worker4工作
11:47:30.907  INFO (BusyWorker.java:31) - threadName=main 线程结束worker5工作