JAVA并发，线程优先级

package com.xt.thinks21_2;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * java线程优先级测试
 * 
 * @author Administrator
 *
 */
public class ThreadPriorityTest implements Runnable {
    private int countDown = 5;
    private int priority;
    private volatile double d;

    public ThreadPriorityTest(int priority) {
        this.priority = priority;
    }

    @Override
    public String toString() {
        // TODO Auto-generated method stub
        return Thread.currentThread() + ":" + countDown;
    }

    @Override
    public void run() {
        // TODO Auto-generated method stub
        Thread.currentThread().setPriority(priority);
        while (true) {
            for (int i = 0; i < 10000000; i++) {
                d += (Math.PI + Math.E) / (double) i;
                if (i % 1000 == 0)
                    Thread.yield();
            }
            System.out.println(this);
            if (--countDown == 0)
                return;
        }
    }

    public static void main(String[] args) {
        ExecutorService es = Executors.newCachedThreadPool();
        for (int i = 0; i < 5; i++)
            es.execute(new ThreadPriorityTest(Thread.MIN_PRIORITY));
        es.execute(new ThreadPriorityTest(Thread.MAX_PRIORITY));
        es.shutdown();
    }
}

线程内部执行耗时操作的时候，设置线程优先级可以有效的调整线程执行顺序（无规律）。