线程优先级、守护线程

一、线程优先级

线程优先级的设置能让优先级高的线程先运行，不过并不是绝对的。主要还是取决于CPU的调度

1.线程优先级测试实例

//线程优先级 public class ThreadDemo12_priority { public static void main(String[] args) { //打印主线程优先级（系统默认为5） System.out.println(Thread.currentThread().getName()+"-->"+Thread.currentThread().getPriority()); MyPriority mp=new MyPriority(); Thread t1=new Thread(mp); Thread t2=new Thread(mp); Thread t3=new Thread(mp); Thread t4=new Thread(mp); Thread t5=new Thread(mp); Thread t6=new Thread(mp); //先设置优先级，再启动 t1.start();//不设置优先级，默认为5 t2.setPriority(1); t2.start(); t3.setPriority(2); t3.start(); t4.setPriority(3); t4.start(); t5.setPriority(8); t5.start(); t6.setPriority(Thread.MAX_PRIORITY); t6.start(); } } class MyPriority implements Runnable{ @Override public void run() { System.out.println(Thread.currentThread().getName()+"-->"+Thread.currentThread().getPriority()); } }

二、线程守护

//守护线程
    //我生前上帝线程会跟着我运行，我死后上帝线程也会结束
public class ThreadDemo13_daemon {
    public static void main(String[] args) {
        MyLife me=new MyLife();
        God god=new God();
        Thread thread=new Thread(god);
        thread.setDaemon(true);//daemon默认是为false
        thread.start();
        new Thread(me).start();

    }
}
//这是上帝线程
class God implements Runnable {

    @Override
    public void run() {
        while (true) {
            try {
                Thread.sleep(50);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            System.out.println("我是上帝，守护着你");
        }
    }
}
//这是自己
class MyLife implements  Runnable{

    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            try {
                Thread.sleep(50);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            System.out.println("我开心的活着");
        }
        System.out.println("我死了============");

    }