线程优先级

线程优先级

1.Java提供了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。
2.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;
3.使用以下方式改变或获取优先级
    getPriority() .setPriority(int xxx)
注意：1.优先级的设定建议在start()调度前
　　　2.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调度的

public class TestPriority implements Runnable{

    @Override
    public void run() {

        System.out.println(Thread.currentThread().getName()+"的优先级"+Thread.currentThread().getPriority());
    }

    public static void main(String[] args) {

        System.out.println(Thread.currentThread().getName()+":"+Thread.currentThread().getPriority());

        TestPriority testPriority=new TestPriority();

        Thread thread = new Thread(testPriority);
        Thread thread1=new Thread(testPriority);
        Thread thread2=new Thread(testPriority);
        Thread thread3=new Thread(testPriority);
        Thread thread4=new Thread(testPriority);

        thread.start();

        thread1.setPriority(Thread.MAX_PRIORITY);  //10
        thread1.start();

        thread2.setPriority(3);
        thread2.start();

        thread3.setPriority(1);
        thread3.start();

        thread4.setPriority(5);
        thread4.start();
    }
}