详解java中的PropertyChangeSupport与PropertyChangeListener

java中的PropertyChangeSupport与PropertyChangeListener配合使用能够实现,绑定属性会在属性值发生变化时,通知所有相关的监听器。

javaBean:

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package com.wang.test.property;
  
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
  
public class TestBean {
  
  protected final PropertyChangeSupport support = new PropertyChangeSupport(this);
    
  private String str;
    
  public String getStr() {
    return str;
  }
  
  public void setStr(String str) {
    support.firePropertyChange("str", this.str, str);
    this.str = str;
  }
    
  public void addPropertyChangeListener(PropertyChangeListener listener) {
    support.addPropertyChangeListener(listener);
  }
    
  public void removePropertyChangeListener(PropertyChangeListener listener) {
    support.removePropertyChangeListener(listener);
  }
}

client:

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package com.wang.test.property;
  
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
  
public class PropertyChangeSupportTest {
  
  public static void main(String[] args) { 
      
    TestBean test = new TestBean();
    test.setStr("ddddd");
    test.addPropertyChangeListener(new PropertyChangeListener1());
    test.setStr("yyyy");
      
    //test.addPropertyChangeListener(new PropertyChangeListener2());
    //test.setStr("hhhhhhf");
  
     
  public static class PropertyChangeListener1 implements PropertyChangeListener{
  
    @Override
    public void propertyChange(PropertyChangeEvent evt) {
      System.out.println( "1: " + evt.getPropertyName() + "  " + evt.getNewValue() + "  " + evt.getOldValue());
        
    }
  }
    
  public static class PropertyChangeListener2 implements PropertyChangeListener{
  
    @Override
    public void propertyChange(PropertyChangeEvent evt) {
      System.out.println( "2: " + evt.getPropertyName() + "  " + evt.getNewValue() + "  " + evt.getOldValue());
        
    }
  }
}

执行PropertyChangeSupportTest 该类的mian方法

1:未打开注释的输出结果:

            1: str yyyy ddddd

2:打开注释的输出结果:

            1: str yyyy ddddd

            1: str hhhhhhf yyyy

            2: str hhhhhhf yyyy

原文地址:https://www.cnblogs.com/tianzg/p/13048369.html