两个线程，循环输出1~100

1. public class Test {  
2.     //state==1表示线程1开始打印，state==2表示线程2开始打印  
3.     private static int state = 1;  
4.       
5.     private static int num1 = 1;  
6.     private static int num2 = 2;  
7.       
8.     public static void main(String[] args) {  
9.         final Test t = new Test();  
10.         new Thread(new Runnable() {  
11.             @Override  
12.             public void run() {  
13.                 while(num1<100){  
14.                     //两个线程都用t对象作为锁，保证每个交替期间只有一个线程在打印  
15.                     synchronized (t) {  
16.                         // 如果state!=1, 说明此时尚未轮到线程1打印, 线程1将调用t的wait()方法, 直到下次被唤醒  
17.                         if(state!=1){  
18.                             try {  
19.                                 t.wait();  
20.                             } catch (InterruptedException e) {  
21.                                 e.printStackTrace();  
22.                             }  
23.                         }  
24.                          // 当state=1时, 轮到线程1打印5次数字  
25.                         for(int j=0; j<5; j++){  
26.                             System.out.println(num1);  
27.                             num1 += 2;  
28.                         }  
29.                         // 线程1打印完成后, 将state赋值为2, 表示接下来将轮到线程2打印  
30.                         state = 2;  
31.                         // notifyAll()方法唤醒在t上wait的线程2, 同时线程1将退出同步代码块, 释放t锁  
32.                         t.notifyAll();  
33.                     }  
34.                 }  
35.             }  
36.         }).start();  
37.           
38.         new Thread(new Runnable() {  
39.             @Override  
40.             public void run() {  
41.                 while(num2<100){  
42.                     synchronized (t) {  
43.                         if(state!=2){  
44.                             try {  
45.                                 t.wait();  
46.                             } catch (InterruptedException e) {  
47.                                 e.printStackTrace();  
48.                             }  
49.                         }  
50.                         for(int j=0; j<5; j++){  
51.                             System.out.println(num2);  
52.                             num2 += 2;  
53.                         }  
54.                         state = 1;  
55.                         t.notifyAll();  
56.                     }  
57.                 }  
58.             }  
59.         }).start();  
60.     }  
61.   
62. }