线程优先级

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.MORM_PRIORITY = 5;
• 使用以下方法改变或获取优先级
  • getPriority() //获取优先级
  • setPriority(int XXX) //修改优先级

虽然线程的优先级越高，按照道理来说越先执行，但真正执行哪个线程还是由cpu调度决定。

package com.Luoking.Thread;
 
public class ThreadPriority implements Runnable{
 
 
 
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName()+"优先级为-->"+Thread.currentThread().getPriority());
    }
 
    public static void main(String[] args) {
        //主线程的默认线程
        System.out.println(Thread.currentThread().getName()+"优先级为-->"+Thread.currentThread().getPriority());
        ThreadPriority Priority = new ThreadPriority();
        Thread T1 = new Thread(Priority,"T1");
        Thread T2 = new Thread(Priority,"T2");
        Thread T3 = new Thread(Priority,"T3");
        Thread T4 = new Thread(Priority,"T4");
        Thread T5 = new Thread(Priority,"T5");
 
        //线程默认优先级
        T1.start();
        //设置优先级
        T2.setPriority(2);
        T2.start();
 
        T3.setPriority(6);
        T3.start();
 
        T4.setPriority(8);
        T4.start();
 
        T5.setPriority(Thread.MAX_PRIORITY);
        T5.start();
    }
 
 
 
}

输出结果

main优先级为-->5
T5优先级为-->10
T4优先级为-->8
T1优先级为-->5
T2优先级为-->2
T3优先级为-->6
//可以看出，优先级越高，不一定越早执行