线程池的优点简介说明

由于创建线程需要消耗资源和时间，所以我们才将创建线程进行池化，
使线程个数控制在合理的范围

为了避免创建线程中消耗资源，当程序启动后，则创建指定数量的线程，我们将这个创建的线程，并称之为“线程池”

public class ThreadPool {
    public static void main(String[] args) {
        threadDemo(100000);
        poolDemo(100000);
    }

    public static void poolDemo(int count) {
        long startTime = System.currentTimeMillis();
        final list<Integer> l = new LinkedList<>();
        ThreadPoolExecutor tp = new ThreadPoolExecutor(1, 10, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(count));
        final Random random = new Random();
        for (int i = 0; i < count; i++) {
            Runnable runnable = new Runnable() {
                @Override
                public void run() {
                    l.add(random.nextInt());
                }
            };
            tp.execute(runnable);
        }
        tp.shutdown();
        try {
            tp.awaitTermination(1, TimeUnit.DAYS);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("ThreadPool spend time:" + (System.currentTimeMillis() - startTime));
        System.out.println(l.size());
    }

    public static void threadDemo(int count) {
        long startTime = System.currentTimeMillis();
        final List<Integer> l = new LinkedList<>();
        final Random random = new Random();
        for (int i = 0; i < count; i++) {
            Thread thread = new Thread(() -> l.add(random.nextInt()));
            thread.start();
            try {
                Thread.join();
            }
            catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("Thread spend time:"+(System.currentTimeMillis() - startTime));
        System.out.println(l.size());
    }
}