线程中wait和notify的一个小例子

Question

今天看了一个关于sleep的面试题，然后自己想了一个关于wait的 具体实现是这样的
有三个buton 分别是hello stop wake 实现的功能是 当点击hello就在控制台输出一个hello 然后点击stop 输出hello就wait指导再点击wake然后中间点了几次hello就一下输出几个hello下面是我写的 但是写不对，线程这东西好久不用都忘了，希望各位指点一下。import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;import javax.swing.JButton;
import javax.swing.JFrame;public class WaitNotifyTest extends JFrame {
private JButton sayHello;
private JButton stop;
private JButton wake;
private boolean flag; public static void main(String[] args) {
new WaitNotifyTest().launch();
} public void launch() {
sayHello = new JButton("hello");
stop = new JButton("stop");
wake = new JButton("wake");
flag = true;
add(sayHello);
add(stop);
add(wake);
sayHello.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent arg0) {
while (flag == false) {
synchronized (this) {
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
System.out.println("hello");
}
}); stop.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent arg0) {
flag = false;
}
}); wake.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent arg0) {
synchronized (this) {
flag = true;
this.notify();
}
}
});
this.setLayout(new FlowLayout());
this.pack();
this.setVisible(true);
}}

Answer 1

一个线程里，一旦进入wait()，线程进入阻塞，谁能唤醒？
修改了一下，楼主参考：
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;import javax.swing.JButton;
import javax.swing.JFrame;public class WaitNotifyTest extends JFrame {
    private JButton sayHello;
    private JButton stop;
    private JButton wake;
    private boolean flag;    static Object ob=new Object(); //用于做同步对象锁。
    public static void main(String[] args) {
        new WaitNotifyTest().launch();
    }    public void launch() {
        sayHello = new JButton("hello");
        stop = new JButton("stop");
        wake = new JButton("wake");
        flag = true;
        add(sayHello);
        add(stop);
        add(wake);
        sayHello.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
new Thread(new Runnable(){ //内部类再创建并启动一个线程
public void run(){
                while (flag == false) {
                    synchronized (WaitNotifyTest.ob) {
                        try {                            WaitNotifyTest.ob.wait(); //不用this了.  } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }
                System.out.println("hello");
            }
    }).start();
    }
        });        stop.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                flag = false;
            }
        });        wake.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                synchronized (WaitNotifyTest.ob) { //这的同步对象也变了。
                    flag = true;
                    WaitNotifyTest.ob.notify();
                }
            }
        });
        this.setLayout(new FlowLayout());
        this.pack();
        this.setVisible(true);
    }}

Answer 2

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;import javax.swing.JButton;
import javax.swing.JFrame;public class WaitNotifyTest extends JFrame {
    private JButton sayHello;
    private JButton stop;
    private JButton wake;
    private boolean flag;    public static void main(String[] args) {
      WaitNotifyTest t=  new WaitNotifyTest();//改哈这里 this不要乱用  由于直接new出来的东西没有引用，不是实体不能被引用
      
      t.launch(); //楼主接分吧
    }    public void launch() {
        sayHello = new JButton("hello");
        stop = new JButton("stop");
        wake = new JButton("wake");
        flag = true;
        add(sayHello);
        add(stop);
        add(wake);
        sayHello.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                while (flag == false) {
                    synchronized (this) {
                        try {
                            this.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }
                System.out.println("hello");
            }
        });        stop.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                flag = false;
            }
        });        wake.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                synchronized (this) {
                    flag = true;
                    this.notify();
                }
            }
        });
        this.setLayout(new FlowLayout());
        this.pack();
        this.setVisible(true);
    }}

Answer 3

改成 WaitNotifyTest.ob.notifyAll(); 就行了 谢谢你 我明白了