PropertyChangeListener接口使用初探

转自：http://vakinge.iteye.com/blog/441908

接口 java.beans.PropertyChangeListener 
顾名思义监听属性改变事件，最近做一些东西需要用到数据绑定相关东西，用到了这个接口。 
这里做一个简单DEMO。 

public class DemoBeans {

    private String demoName;

    PropertyChangeSupport listeners = new PropertyChangeSupport(this);

    public DemoBeans() {
        demoName = "initValue";
    }


    public String getDemoName() {
        return demoName;
    }


    public void setDemoName(String demoName) {
        String oldValue = this.demoName;
        this.demoName = demoName;
        //发布监听事件
        firePropertyChange("demoName", oldValue, demoName);

    }

    public void addPropertyChangeListener(PropertyChangeListener listener) {
        listeners.addPropertyChangeListener(listener);
    }

    public void removePropertyChangeListener(PropertyChangeListener listener){
        listeners.addPropertyChangeListener(listener);
    }


    /**
     * 触发属性改变的事件
     */
    protected void firePropertyChange(String prop, Object oldValue, Object newValue) {
        listeners.firePropertyChange(prop, oldValue, newValue);
    }

}

测试类： 

public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {
        DemoBeans beans = new DemoBeans();
        beans.addPropertyChangeListener(new PropertyChangeListener(){

            public void propertyChange(PropertyChangeEvent evt) {
                System.out.println("OldValue:"+evt.getOldValue());
                System.out.println("NewValue:"+evt.getNewValue());
                System.out.println("tPropertyName:"+evt.getPropertyName());
            }});
        beans.setDemoName("test");
    }

}

运行结果： 

OldValue:initValue 
NewValue:test 
tPropertyName:demoName