1.5线程优先级

在操作系统中，优先级越高的线程，其任务会优先被CPU执行

在Java中使用setPriority（）来设置线程优先级，优先级分为[1,2…9,10]十个等级，超出此范围则会抛出异常

线程优先级能“继承”

        // 测试1
        System.out.println("main begin:" + Thread.currentThread().getPriority());
        System.out.println("main end:" + Thread.currentThread().getPriority());
        Thread1a thread1a = new Thread1a();
        thread1a.start();
        // 测试2
        System.out.println("main begin:" + Thread.currentThread().getPriority());
        Thread.currentThread().setPriority(6);
        System.out.println("main end:" + Thread.currentThread().getPriority());
        Thread1a thread1a = new Thread1a();
        thread1a.start();

package com.myThread;

public class Thread1a extends Thread {
@Override
public void run() {
    super.run();
    System.out.println("Thread1a:"+this.currentThread().getPriority());
    Thread1b thread1b=new Thread1b();
    thread1b.start();
}
}

package com.myThread;

public class Thread1b extends Thread {
@Override
public void run() {
    super.run();
    System.out.println("Thread1b:"+this.currentThread().getPriority());
}
}

测试1打印结果

main begin:5
main end:5
Thread1a:5
Thread1b:5


测试2打印结果

main begin:5
main end:6
Thread1a:6
Thread1b:6


优先级规则

优先级与调用线程的先后顺序无关
优先级高只是代表获取资源多，不代表一定先完成，因为线程是随机执行的