线程池,线程池常见的几种用法

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);

3. 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);

4. 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);
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15