10.线程的优先级

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，1~10

Tread.MIN_PRIORITY = 1;Tread.MAX_PRIORITY = 10;Tread.NORM_PRIORITY = 5; 默认 使用以下方法获取或改变优先级

getPriority()setPriority(int xxx) 优先级的设置建议再start()调度之前优先级低只能意味者获取调度的概率低，并不是优先级低就不会被调用了，这都是看cpu的调度

package com.state;

public class TestPriority {
    public static void main(String[] args) {
        // 获取main线程的优先级
        System.out.println(Thread.currentThread().getName()+"-->" + Thread.currentThread().getPriority());

        TestPriority2 p2 = new TestPriority2();

        Thread t1 = new Thread(p2);
        Thread t2 = new Thread(p2);
        Thread t3 = new Thread(p2);
        Thread t4 = new Thread(p2);
        Thread t5 = new Thread(p2);

        t1.start();

        t2.setPriority(Thread.MIN_PRIORITY); // 1
        t2.start();

        t3.setPriority(Thread.MAX_PRIORITY); // 10
        t3.start();

        // 小于1 大于10 会抛出异常
        // t4.setPriority(-1);
        // t4.start();

        // t5.setPriority(11);
        // t5.start();
    }
}

class TestPriority2 implements Runnable{
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName() + "-->" + Thread.currentThread().getPriority());
    }
}