线程优先级只使用三个等级

 1 public class Client {
 2     public static void main(String[] args){
 3         //启动20个不同优先级的线程
 4         for (int i = 0; i < 20; i++) {
 5             new TestThread().start(i % 10 + 1);
 6         }
 7 
 8     }
 9 }
10 
11 class TestThread implements Runnable {
12     //启动线程
13     public void start(int _priority) {
14         Thread t = new Thread(this);
15         //设置线程优先级
16         t.setPriority(_priority);
17         t.start();
18     }
19 
20     @Override
21     public void run() {
22         //消耗CPU的计算，性能差的机器，请修改循环限制
23         for (int i = 0; i < 100000; i++) {
24             Math.hypot(Math.pow(924526789,i),Math.cos(i));
25         }
26         //输出线程优先级
27         System.out.println("Priority:" + Thread.currentThread().getPriority());
28 
29     }
30 }

Priority:10
Priority:7
Priority:1
Priority:8
Priority:3
Priority:6
Priority:3
Priority:2
Priority:4
Priority:8
Priority:9
Priority:9
Priority:10
Priority:2
Priority:6
Priority:7
Priority:5
Priority:5
Priority:4
Priority:1

public class Thread implements Runnable {
    /**
     * The minimum priority that a thread can have.
     */
    public final static int MIN_PRIORITY = 1;

   /**
     * The default priority that is assigned to a thread.
     */
    public final static int NORM_PRIORITY = 5;

    /**
     * The maximum priority that a thread can have.
     */
    public final static int MAX_PRIORITY = 10;
}