2012-01-25 29 views
2
class SelfishRunner extends Thread{ 
    private int tick = 1; 
    private int num ; 
    public  SelfishRunner(int x){ 
      this.num = x; 
    } 
    @Override 
    public void run(){ 
      try{ 
       while(tick < 400000){ 
        Thread.sleep(250); 
        if((tick%50000) == 0){ 
         System.out.println(" Thread# "+num+","+Thread.currentThread().getName()+", tick "+tick); 
         } 
        tick++; 
       } 
      }catch(Exception e){ 
        System.out.println(e); 
      } 
     } 
    } 


    public class RaceDemo{ 
      private final static int NUMRUNNERS = 2; 
      public static void main(String[] args){ 
       SelfishRunner[] runners = new SelfishRunner[NUMRUNNERS]; 
       for(int x=0,y=1; x < NUMRUNNERS; x++){ 
         runners[x] = new SelfishRunner(x); 
         runners[x].setPriority(y++); 
       } 
       runners[0].setName("JEEPERS"); 
       runners[1].setName("KREEPERS"); 
       for(int x=0; x < NUMRUNNERS; x++){ 
        runners[x].start(); 
       } 
      } 
    } 

上面的代码试图创建一个竞争条件,但在SelfRunner.run调用Thread.sleep(250)停止程序执行,而不进行打印输出到命令行。了Thread.sleep方法停止线程permenantly

当我注释掉该行时,它可以正常工作。

有人可以告诉我为什么吗?

+8

'Thread.sleep(250)'将使线程睡眠250毫秒(1/4秒)。它将每50,000次迭代打印一次。这意味着在打印内容之前,您必须等待50,000/4 = 12,500秒(3小时28分20秒)。你有这么多的耐心吗? – Jesper

回答

7

你意识到你每50000/4秒只打印一些东西,对吧?您可能想再等一会儿。 :)

+2

现在时间到了 - 是否印有什么? –