class MyThread implements Runnable
{ public void run(){ for(int i=0; i<50; i++){ System.out.println(Thread.currentThread().getName() + "...present=====" +i); } } } public class Demo943 { public static void main(String args[]){ MyThread my = new MyThread();Thread t = new Thread(my);t.start();for(int i=0; i<50; i++){ if(i>10){ try{ t.join();}catch (Exception e){ }}System.out.println("Main...." + i);} } }这是未经休眠的运行结果：
Main....0
Thread-0... Main....1 Thread-0... Main....2 Thread-0... Thread-0... Main....3 Thread-0... Main....4 Thread-0... Main....5 Thread-0... Main....6 Thread-0... Main....7 Thread-0... Main....8 Thread-0... Main....9 Thread-0... Main....10 Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Thread-0... Main....11 Main....12 Main....13 Main....14 Main....15 Main....16 Main....17 Main....18 Main....19 Main....20 Main....21 Main....22 Main....23 Main....24 Main....25 Main....26 Main....27 Main....28 Main....29 Main....30 Main....31 Main....32 Main....33 Main....34 Main....35 Main....36 Main....37 Main....38 Main....39 Main....40 Main....41 Main....42 Main....43 Main....44 Main....45 Main....46 Main....47 Main....48 Main....49================================================================================
class MyThread implements Runnable
{ public void run() { for(int i=0; i<50; i++) { try { Thread.sleep(500); //经过休眠处理 } catch (Exception e) { } System.out.println(Thread.currentThread().getName() + "...present=====" +i); } } } public class Demo943 { public static void main(String args[]) { MyThread my = new MyThread(); Thread t = new Thread(my); t.start(); for(int i=0; i<50; i++) { if(i>10) { try { t.join(); } catch (Exception e) { } } System.out.println("Main...." + i); } }}
休眠处理的结果：
Main....0
Main....1 Main....2 Main....3 Main....4 Main....5 Main....6 Main....7 Main....8 Main....9 Main....10 Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Thread-0.. Main....11 Main....12 Main....13 Main....14 Main....15 Main....16 Main....17 Main....18 Main....19 Main....20 Main....21 Main....22 Main....23 Main....24 Main....25 Main....26 Main....27 Main....28 Main....29 Main....30 Main....31 Main....32 Main....33 Main....34 Main....35 Main....36 Main....37 Main....38 Main....39 Main....40 Main....41 Main....42 Main....43 Main....44 Main....45 Main....46 Main....47 Main....48 Main....49对比可以发现，未经过休眠处理的线程，会跟Main线程争抢运行；而经过休眠处理之后，Main会趁其休眠的时间抢先运行。
这对于已入门Java的人来说虽然不是什么，但是通过这个小实验，清楚了Main线程的存在，并且了解到线程争抢之激烈。。。。