Java volatile 的测试（Java代码实战-004）详解编程语言

package Threads; 
 
/** 
 * Created by xfyou 2018/5/21 16:07. 
 */ 
public class VolatileTest { 
 
    private static volatile int MY_INT = 0; 
 
    /** 
     * 主线程启动2个测试子线程 
     * 
     * @param args null 
     */ 
    public static void main(String[] args) { 
        new ChangeListener().start(); 
        new ChangeMaker().start(); 
    } 
 
    /** 
     * 此线程负责对MY_INT值改变的侦听，如果有改变就会打印出来 
     */ 
    static class ChangeListener extends Thread { 
        @Override 
        public void run() { 
            int local_value = MY_INT; 
            while (local_value < 5) { 
                if (local_value != MY_INT) { 
                    System.out.println("Got Change for MY_INT : " + MY_INT); 
                    local_value = MY_INT; 
                } 
            } 
        } 
    } 
 
    /** 
     * 此线程负责改变MY_INT的值 
     */ 
    static class ChangeMaker extends Thread { 
        @Override 
        public void run() { 
            int local_value = MY_INT; 
            while (MY_INT < 5) { 
                System.out.println("Incrementing MY_INT to " + (local_value + 1)); 
                MY_INT = ++local_value; 
                try { 
                    Thread.sleep(500); 
                } catch (InterruptedException e) { 
                    e.printStackTrace(); 
                } 
            } 
        } 
    } 
}

Incrementing MY_INT to 1 
Got Change for MY_INT : 1 
Incrementing MY_INT to 2 
Got Change for MY_INT : 2 
Incrementing MY_INT to 3 
Got Change for MY_INT : 3 
Incrementing MY_INT to 4 
Got Change for MY_INT : 4 
Incrementing MY_INT to 5 
Got Change for MY_INT : 5

Incrementing MY_INT to 1 
Incrementing MY_INT to 2 
Incrementing MY_INT to 3 
Incrementing MY_INT to 4 
Incrementing MY_INT to 5