mxml日期显示使用

mxml代码：
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
               xmlns:s="library://ns.adobe.com/flex/spark"
               xmlns:mx="library://ns.adobe.com/flex/mx"
               minWidth="" minHeight="">
    <fx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
            import mx.controls.Alert;
            public var arr:ArrayCollection = new ArrayCollection([
                {label:"Dan Orlando"},
                {label:"Tarip Ahmeh"},
                {label:"John C Bland IT"}
            ]);

        ]]>
    </fx:Script>
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    <mx:List id="myFriends" dataProvider="{arr}"/>
</s:Application>

User类：
package com.xyw.model
{
    public class User
    {
        public var id:Number;
        public var username:String;
        public var birthday:Date;
        public function User()
        {
        }
    }
}