详解java中的PropertyChangeSupport与PropertyChangeListener

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：

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：

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());

    }
  }
}

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