thread-->SimplePriorities

volatile :含义和用法参考资料 http://www.iteye.com/topic/109150

 

package thread;

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

/** 优先级的测试类,一般情况下不需要用到优先级 */
public class SimplePriorities implements Runnable
{
    private int countDown = 5;
    
    private volatile double d; // 直接在主存操作这个变量
    
    private int priority;
    
    public SimplePriorities(int priority)
    {
        this.priority = priority;
    }
    
    public String toString()
    {
        return Thread.currentThread() + " : " + countDown;
    }
    
    public void run()
    {
        Thread.currentThread().setPriority(priority);// 设置优先级，需要在run开头部分设置
        while (true)
        {
            for (int i = 1; i < 100000; 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 service = Executors.newCachedThreadPool();
        for (int i = 0; i < 5; i++)
            service.execute(new SimplePriorities(Thread.MIN_PRIORITY));
        service.execute(new SimplePriorities(Thread.MAX_PRIORITY));
        service.shutdown();
    }
}