java5線程池

1）創建固定大小線程池

public class ThreadTest {
    public static void main(String[] args) {
        //ExecutorService executorService = Executors.newFixedThreadPool(2); //創建一個可重用固定線程數的線程池
        //ExecutorService executorService = Executors.newSingleThreadExecutor(); //創建單任務線程池
        ExecutorService executorService = Executors.newCachedThreadPool(); //創建一個可變尺寸的線程池
        Task task1 = new Task();
        Task task2 = new Task();
        Task task3 = new Task();
        executorService.execute(task1);
        executorService.execute(task2);
        executorService.execute(task3);
        executorService.shutdown();
    }
}

class Task implements Runnable {
    public void run() {
        System.out.println(Thread.currentThread().getName() + " Hello");
    }
}

對於大小固定的線程池，如：newFixedThreadPool(int size)和newSingeThreadExecutor(),當要加入的任務大於線程池的大小時，則任務需要排隊等待。

2）創建可變尺寸線程池

public class ThreadTest {
    public static void main(String[] args) {
        ExecutorService executorService = Executors.newCachedThreadPool(); //創建一個可變尺寸的線程池
        Task task1 = new Task();
        Task task2 = new Task();
        Task task3 = new Task();
        executorService.execute(task1);
        executorService.execute(task2);
        executorService.execute(task3);
        executorService.shutdown();
    }
}

class Task implements Runnable {
    public void run() {
        System.out.println(Thread.currentThread().getName() + " Hello");
    }
}

3）創建延遲連接線程池

public class ThreadTest {
    public static void main(String[] args) {
        ScheduledExecutorService executorService = Executors.newScheduledThreadPool(2);
        Task task1 = new Task();
        Task task2 = new Task();
        Task task3 = new Task();
        executorService.execute(task1);
        executorService.scheduleAtFixedRate(task2,0L,2,TimeUnit.HOURS); //此方法表示在指定的週期內循環執行task2任務，2表示循環的週期，TimeUtils.HOURS表示循                                                                                                                                                                 環週期的時間單位，此處是小時
        executorService.schedule(task3,10, TimeUnit.HOURS); //task2是實現Runnable接口的任務，10時延遲的時間，TimeUtil.HOURS是延遲時間的計量單位，在此處是小                                                                                                                                                     時
        executorService.shutdown();
    }
}

class Task implements Runnable {
    public void run() {
        System.out.println(Thread.currentThread().getName() + " Hello");
    }
}