java5线程池

1）创建固定大小线程池

public class ThreadTest {  
    public static void main(String[] args) {  
        //ExecutorService executorService = Executors.newFixedThreadPool(2); //创建一个可重用固定线程数的线程池  
        //ExecutorService executorService = Executors.newSingleThreadExecutor(); //创建单任务线程池  
        ExecutorService executorService = Executors.newCachedThreadPool(); //创建一个可变尺寸的线程池  
        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");  
    }  
} 

对于大小固定的线程池，如：newFixedThreadPool(int size)和newSingeThreadExecutor(),当要加入的任务大于线程池的大小时，则任务需要排队等待。

2）创建可变尺寸线程池

public class ThreadTest {  
    public static void main(String[] args) {  
        ExecutorService executorService = Executors.newCachedThreadPool(); //创建一个可变尺寸的线程池  
        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）创建延迟连接线程池

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周期内循环执行task2任务，2表示循环的周期，TimeUtils.HOURS表示循                                                                                                                                                                 环周期的时间单位，此处是小时  
        executorService.schedule(task3,10, TimeUnit.HOURS); //task2是实现Runnable接口的任务，10时延迟的时间，TimeUtil.HOURS是延迟时间的计量单位，在此处是小                                                                                                                                                     时  
        executorService.shutdown();  
    }  
}  
 
class Task implements Runnable {  
    public void run() {  
        System.out.println(Thread.currentThread().getName() + " Hello");  
    }  
}