线程池,线程池常见的几种用法

小鱼儿 2024-02-19 13:34 36阅读 0赞

### 线程池 ###

> 线程池解决的问题:频繁的创建线程对象和多个线程之间进行上下文切换,是非常耗费时间和资源的,所以jdk1.5中提出了线程池技术同时能够更方便的管理线程

1.  创建固定数量的线程

ExecutorService pool = Executors.newFixedThreadPool(2);
    Runnable task = new Runnable() {
        @Override
        public void run() {
            while (true) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName());
            }
        }
    };
    pool.execute(task);
    pool.execute(task);
    pool.execute(task);//线程池的带下只有两个   现在这个任务在其等待队列中排队等候

1.  创建可变大小的线程池

ExecutorService pool = Executors.newCachedThreadPool();
    Runnable task = new Runnable() {
        @Override
        public void run() {
            while (true) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName());
            }
        }
    };
    pool.execute(task);
    pool.execute(task);
    pool.execute(task);

1.  创建独立任务的线程池

ExecutorService pool = Executors.newSingleThreadExecutor();
    Runnable task = new Runnable() {
        @Override
        public void run() {
            while (true) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName());
            }
        }
    };
    pool.execute(task);
    pool.execute(task);
    pool.execute(task);

1.  创建可调度的线程池

ScheduledExecutorService threadPool = Executors.newScheduledThreadPool(2);
    Runnable task = new Runnable() {
    @Override
    public void run() {
    while (true) {
    try {
    Thread.sleep(1000);
    } catch (InterruptedException e) {
    e.printStackTrace();
    }
    System.out.println(Thread.currentThread().getName());
    }
    }
    };
    threadPool.schedule(task, 2000, TimeUnit.MILLISECONDS);