十八、线程优先级

Java提供一个线程调度器来监控程序中启动后进入就绪状态的所有线程，线程调度器按照优先级决定应该调度哪个线程来执行。

线程的优先级用数字表示，范围从1~10.

• Thread.MIN_PRIORITY = 1;
• Thread.MAX_PRIORITY = 10;
• Thread.NORM_PRIORITY = 5;

使用以下方式改变或获取优先级

• getPriority()
• setPriority(int xxx)

public class ThreadPriority implements Runnable{

    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName()+"的优先级是："+Thread.currentThread().getPriority());
    }


    public static void main(String[] args) {

        Thread.currentThread().setName("main");
        System.out.println(Thread.currentThread().getName()+"的优先级是："+Thread.currentThread().getPriority());

        ThreadPriority t = new ThreadPriority();

        Thread t1 = new Thread(t,"t1");
        Thread t2 = new Thread(t,"t2");
        Thread t3 = new Thread(t,"t3");
        Thread t4 = new Thread(t,"t4");
        Thread t5 = new Thread(t,"t5");

        t1.setPriority(Thread.MIN_PRIORITY);
        t2.setPriority(3);
        t3.setPriority(Thread.NORM_PRIORITY);
        t4.setPriority(8);
        t5.setPriority(Thread.MAX_PRIORITY);

        t1.start();
        t2.start();
        t3.start();
        t4.start();
        t5.start();
    }
}

 

结果：优先级低只是意味着获得调度的概率低，并不是优先级低就不会被调用了，这都是看CPU的调度。