1. 改成static也不行 private static boolean isRunning = true; volatile關鍵字主要用於線程變量在多個線程之間的可見

 1 public class RunThread extends Thread{
 2     private volatile  boolean isRunning = true;
 3     public void setRunning(boolean isRunning) {
 4         System.out.println(Thread.currentThread().getName()+"線程setRunning");
 
 5         this.isRunning = isRunning;
 6     }
 7 
 8     public void run(){
 9         System.out.println(Thread.currentThread().getName()+"進入run方法...");
10         while(isRunning) {
11             //System.out.println(Thread.currentThread().getName()+"線程isRunning");
12         }
13         System.out.println(Thread.currentThread().getName()+"線程終止");
 
14     }
15 
16     public static void main(String[] args) throws Exception {
17         RunThread rt = new RunThread();
18         rt.start();
19         Thread.sleep(3000);
20         rt.setRunning(false);
21         System.out.println(Thread.currentThread().getName()+"線程isRunning值被設置成false");
22         Thread.sleep(100);
 
23         System.out.println(Thread.currentThread().getName()+"::"+rt.isRunning);
24     }
25     /* 不加volatile關鍵字, 主內存中的isRunning不會被刷新,永遠都是true.所以線程不會終止,加了會把rt線程的工作內存變量刷新到主內存
26      * Thread-0進入run方法...
27         main線程setRunning
28         main線程isRunning值被設置成false
29         main::false
30      */
31 }

多線程7---volatile關鍵字,刷新線程工作空間內存到主內存中去,即保持同步