【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)

优先级的设置建议在start()调度前

#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调度。

package state;
​
//测试线程优先级
public class TestPriority {
    public static void main(String[] args) {
        //主线程优先级
        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.setPriority(1);
        t1.start();
​
        t2.setPriority(3);
        t2.start();
​
        t3.setPriority(2);
        t3.start();
​
        t4.setPriority(Thread.MAX_PRIORITY);
        t4.start();
​
        t5.setPriority(Thread.NORM_PRIORITY);
        t5.start();
​
        t6.setPriority(8);
        t6.start();
​
    }
}
class MyPriority implements Runnable{
​
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName()+"--->"+Thread.currentThread().getPriority());
    }
}