java线程池线程回收

注意： 一定要将线程回收，否则程序会一直等待！！ 也可以关闭线程池，来退出程序，但是这样会导致新的任务无法执行！！
线程回收之后，有新的任务到来就会自动新建线程。

class Task implements Runnable{    private int x;            //线程编号    public Task(int x) {        this.x = x;    }    public void run() {        System.out.println(x + " thread doing something!");        System.out.println("第" + x + "个线程执行完毕");    }}

 

1、设置线程池线程最大空闲时间，超出这个时间，对线程进行回收

 

不回收效果（程序一直等待，不退出）：

    public static void main(String[] args) throws InterruptedException {        ThreadPoolExecutor threadPool = new ThreadPoolExecutor(                5, 5,                1, TimeUnit.SECONDS,                new ArrayBlockingQueue<Runnable>(10, false),                new ThreadPoolExecutor.CallerRunsPolicy()        );        for (int i = 1; i <= 5; i++) {            threadPool.execute(new Task(i));        }    }

 

回收效果：

    public static void main(String[] args) throws InterruptedException {        ThreadPoolExecutor threadPool = new ThreadPoolExecutor(                5, 5,                1, TimeUnit.SECONDS,                new ArrayBlockingQueue<Runnable>(10, false),                new ThreadPoolExecutor.CallerRunsPolicy()        );        threadPool.allowCoreThreadTimeOut(true);  //线程的最大空闲时间，超出这个时间将进行回收        for (int i = 1; i <= 5; i++) {            threadPool.execute(new Task(i));        }    }

 

2、关闭线程池（关闭之后，有新任务却不会执行）

public static void main(String[] args) throws InterruptedException {        ThreadPoolExecutor threadPool = new ThreadPoolExecutor(                5, 5,                1, TimeUnit.SECONDS,                new ArrayBlockingQueue<Runnable>(10, false),                new ThreadPoolExecutor.CallerRunsPolicy()        );        for (int i = 1; i <= 5; i++) {            threadPool.execute(new Task(i));        }        threadPool.shutdown();        try {            //Thread.sleep(10*1000);        } catch (Exception e) {            e.printStackTrace();        }        for (int i = 6; i <= 10; i++) {            threadPool.execute(new Task(i));        }    }