執行緒優先順序

• Java提供一個執行緒排程器來監控程式中啟動後進入就緒狀態的所有執行緒，執行緒排程器按照優先順序決定應該排程哪個執行緒來執行。
• 執行緒的優先順序用數字表示，範圍從1~10.
  • Thread.MIN_PRIORITY = 1;
  • Thread.MAX_PRIORITY = 10;
  • Thread.NORM_PRIORITY = 5;
• 使用以下方式改變或獲取優先順序
  • getPriority() . setPriority(int xxx)

優先順序的設定建議在start()排程前
優先順序低只是意味著獲得排程的概率低.並不是優先順序低就不會被呼叫了.這都是看CPU的排程

package com.wang.multiThread.state;


import com.wang.snake.StartGame;

//測試執行緒的優先順序
public class TestPriority {
    public static void main(String[] args) {
        //主執行緒預設優先順序
        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);

        //先設定優先順序，再啟動
        t1.start();

        t2.setPriority(1);
        t2.start();

        t3.setPriority(4);
        t3.start();

        t4.setPriority(Thread.MAX_PRIORITY);//MAX_PRIORITY=10
        t4.start();

//        t5.setPriority(-1);
//        t5.start();
//
//        t6.setPriority(11);
//        t6.start();
    }
}

class MyPriority implements Runnable {

    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName() + "--->" + Thread.currentThread().getPriority());
    }
}