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 xxxx)
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

public class TestPriority extends Thread{

    public static void main(String[] args) {
        // 主线程默认优先级
        System.out.println(Thread.currentThread().getName()+"--->"+Thread.currentThread().getPriority());
        MyPriority myPriority = new MyPriority();
        Thread t1 = new Thread(myPriority);
        Thread t2 = new Thread(myPriority);
        Thread t3 = new Thread(myPriority);
        Thread t4 = new Thread(myPriority);
        Thread t5 = new Thread(myPriority);
        Thread t6 = new Thread(myPriority);

        // 先设置优先级，再启动
        t1.start();
        t2.setPriority(1);
        t2.start();
        t3.start();
        t4.setPriority(Thread.MAX_PRIORITY);
        t4.start();

        t5.setPriority(8);
        t5.start();

        t6.setPriority(4);
        t6.start();
    }
}


class MyPriority implements Runnable{

    public void run(){
        System.out.println(Thread.currentThread().getName()+"--->"+Thread.currentThread().getPriority());
    }

}