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JavaBean的绑定属性及约束属性

Posted on 2010-12-19 14:36  Adam哥  阅读(2242)  评论(0)  编辑  收藏  举报

Bean主体类

package Adam.Bean;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.beans.PropertyVetoException;
import java.beans.VetoableChangeListener;
import java.beans.VetoableChangeSupport;

public class MyJavaBean {
	public MyJavaBean() {
		propertySupport = new PropertyChangeSupport(this);
		vetoableSupport = new VetoableChangeSupport(this);
	}

	public void setSex(String newSex) {
		if (!newSex.equals(sex)) {
			String oldValue = sex;
			// 属性验证
			try {
				vetoableSupport.fireVetoableChange("changesex", sex, newSex);
				// 没的被阻止
				sex = newSex;
			} catch (Exception e) {
				System .out.println("禁止修改");
			}
			
			propertySupport.firePropertyChange("changesex", oldValue, newSex);
		}
	}
	public String getSex()
	{
		return this.sex;
	}
	public void addPropertyChangeListener(PropertyChangeListener listener) {
		propertySupport.addPropertyChangeListener(listener);
	}

	public void removePropertyChangeListener(PropertyChangeListener listener) {
		propertySupport.removePropertyChangeListener(listener);
	}

	public void addVetoableChangeListener(VetoableChangeListener listener) {
		vetoableSupport.addVetoableChangeListener(listener);
	}

	public void removeVetoableChangeListener(VetoableChangeListener listener) {
		vetoableSupport.removeVetoableChangeListener(listener);
	}

	

	private String sex="male";
	PropertyChangeSupport propertySupport;
	VetoableChangeSupport vetoableSupport;
}

事件类

package Adam.Bean;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyVetoException;
import java.beans.VetoableChangeListener;

public class MyJavaBeanPropertyListener implements PropertyChangeListener,
		VetoableChangeListener {

	@Override
	public void vetoableChange(PropertyChangeEvent evt) throws PropertyVetoException {
		if (evt.getNewValue().equals("female")) {
			// 处理监听到的事件
			System.out.println("\"NewValue:\"" + evt.getNewValue() + "\"OldValue:\"" + evt.getOldValue() + "\"");
			throw new PropertyVetoException("禁止变性", evt);
		}
	}

	@Override
	public void propertyChange(PropertyChangeEvent evt) {
			System.out.println("\"NewValue:\"" + evt.getNewValue() + "\"OldValue:\"" + evt.getOldValue() + "\"");
	}
}

JSP文件

<%@page import="Adam.Bean.MyJavaBeanPropertyListener"%>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="UTF-8"%>
    <jsp:useBean id="myBean" class="Adam.Bean.MyJavaBean" scope="page"></jsp:useBean>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%

myBean.addPropertyChangeListener(new MyJavaBeanPropertyListener());
myBean.addVetoableChangeListener(new MyJavaBeanPropertyListener());
%>
<jsp:getProperty property="sex" name="myBean"/>
<jsp:setProperty property="sex" name="myBean" value="female"/>
<br/>
<jsp:getProperty property="sex" name="myBean"/>
</body>
</html>

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