线程池threadPools

1.线程池是用来存储线程的容器

2.Executors.newFixedThreadPool(int n);创建线程池,并且设置线程池的容量为n

3.submit开启线程

4.会返回一个对象future

5.可以通过future.get()获取线程值

public class ThreadPoolTest {
    
    public static void main(String[] args) {
        
    //1.创建线程池对象,规定有几个线程,如果线程满了,就处于等待状态
    ExecutorService service = Executors.newFixedThreadPool(3);
    //2.提交线程
    service.submit(new Demo_02Runnable());
    service.submit(new Demo_02Runnable());
    service.submit(new Demo_02Runnable());
    Future<?> future = service.submit(new Demo_02Runnable());
    try {
        System.out.println(future.get());//返回null,因为实现的是Runnable接口,run方法返回值为void
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (ExecutionException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    //3.关闭
    service.shutdown();
    }

}