Java多线程间的数据共享

下面的程序演示了一个对象被两个线程访问的方法，"monitor.gotMessage();"这一句虽然是monitor对象的方法，但却是运行在"MyObject"的线程里，而不是"monitor"线程里。

BusyWaiting.java:

public class BusyWaiting { 
    public static void main(String[] args) {
        Monitor monitor = new Monitor(); 
        MyObject o = new MyObject(monitor); 
        new Thread(o, " MyObject ").start(); 
        new Thread(monitor, " monitor ").start(); 
        System.out.println("main thread exit..."); 
    } 
} 

MyObject.java

import java.util.concurrent.TimeUnit;
public class MyObject implements Runnable {
    private final Monitor monitor;
    public MyObject(Monitor monitor) {
        this.monitor = monitor;
    }
    public void run() {
        try {
            TimeUnit.SECONDS.sleep(3);
            System.out.println("i'm going.");
            monitor.gotMessage();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
} 



Monitor.java

public class Monitor implements Runnable { 
    private volatile boolean go = false; 
    public void gotMessage() throws InterruptedException { 
        go = true; 
    } 
    public void watching() { 
        while (go == false); 
        System.out.println("He has gone."); 
    } 
    public void run() { 
        watching(); 
    } 
}

另外采用

MyObject o = new MyObject(monitor); 
new Thread(o, " thread1 ").start(); 
new Thread(o, "thread2").start();

也是一种常用的多个线程共享数据的方式，

Java多线程间的数据共享

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