多线程技术: 两个线程交替打印奇数和偶数

1. 要打印的资源

 1 package com.mytest.thread;
 2 
 3 /**
 4  * 要打印的资源
 5  * 
 6  */
 7 public class Num {
 8     int i = 1;
 9     // 两个线程看， 交替执行的一个标志
10     boolean flag = false;
11 }

2. 打印奇数的线程

 1 package com.mytest.thread;
 2 
 3 public class PrintOdd implements Runnable {
 4     Num num;
 5 
 6     public PrintOdd(Num num) {
 7         this.num = num;
 8 
 9     }
10 
11     public void run() {
12         while (num.i <= 100) {
13             synchronized (num) {
14                 if (num.flag) {
15                     try {
16                         num.wait();
17                     } catch (Exception e) {
18                         System.out.println(e.getMessage());
19                     }
20 
21                 } else {
22                     System.out.println("奇数----" + num.i);
23                     num.i++;
24                     num.flag = true;
25                     num.notify();
26                 }
27 
28             }
29         }
30     }
31 }

3. 打印偶数的线程

 1 package com.mytest.thread;
 2 
 3 public class PrintEven implements Runnable {
 4 
 5     Num num;
 6 
 7     public PrintEven(Num num) {
 8         this.num = num;
 9 
10     }
11 
12     public void run() {
13         while (num.i <= 100) {
14             synchronized (num) {// 必须要用同意吧锁对象，这个对象是num
15                 if (!num.flag) {
16                     try {
17                         num.wait();// wait()函数必须和锁死同一个
18                     } catch (Exception e) {
19                         System.out.println(e.getMessage());
20                     }
21 
22                 } else {
23                     System.out.println("偶数----" + num.i);
24                     num.i++;
25                     num.flag = false;
26                     num.notify();
27                 }
28 
29             }
30         }
31     }
32 
33 }

4. 主函数

 1 package com.mytest.thread;
 2 
 3 public class Main {
 4     public static void main(String[] args) {
 5 
 6         Num num = new Num();
 7 
 8         PrintOdd printOdd = new PrintOdd(num);
 9         PrintEven printEven = new PrintEven(num);
10 
11         Thread thread1 = new Thread(printOdd);
12         Thread thread2 = new Thread(printEven);
13 
14         thread1.start();
15         thread2.start();
16     }
17 }