Flex DateFormatter格式化时间异常处理

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Flex自带的mx:DateFormatter在格式化时间的时候有异常，我们看一简单demo。在application中定义dateformatterr如下：

<fx:Declarations>

<mx:DateFormatter id="format" formatString="YYYY-MM-DD HH:NN:SS"/>

</fx:Declarations>

假设，要格式化的日期时间为2010-12-2 0:48:46，调用format.format函数后，我们惊异地发现返回的格式化字串为:”2010-12-02 24:48:46”，看DateFormatter源码发现，只要小时为0都转换为24，用户看到”2010-12-02 24:48:46”非常不可思议。

当初因为没有好好看api，还费点周折去重新实现了一个DateFormatter，明显是简单问题复杂化（虽然知道了其格式化原理），实际上HH显示的1-24小时格式，而JJ显示的是0-23小时格式，因此只要设置formatString="YYYY-MM-DD JJ:NN:SS"即可。

解决：

新建一个DateFormatter继承mx: DateFormatter，重写format函数即可，假设新建的DateFormatter为DateFormatterEX。由于format函数用到了StringFormatter类，而该类被标记为[ExcludeClass]，即自己写的代码不能使用StringFormatter。没办法，新建一个StringFormatterEX类，把StringFormatter代码全部复制过来吧。

DateFormatterEX代码如下：

package com.marcus.flex.formatter

{

import mx.formatters.DateBase;

import mx.formatters.DateFormatter;

public class DateFormatterEX extends DateFormatter

{

private static const VALID_PATTERN_CHARS:String = "Y,M,D,A,E,H,J,K,L,N,S,Q";

public function DateFormatterEX()

{

}

private static function setValue(value:Object, key:int):String

{

var result:String = "";

var vLen:int = value.toString().length;

if (vLen < key)

{

var n:int = key - vLen;

for (var i:int = 0; i < n; i++)

{

result += "0"

}

result += value.toString();

return result;

}

private static function extractTokenDate(date:Date,

tokenInfo:Object):String

{

var result:String = "";

var key:int = int(tokenInfo.end) - int(tokenInfo.begin);

var day:int;

var hours:int;

switch (tokenInfo.token)

{

case "Y":

{

// year

var year:String = date.getFullYear().toString();

if (key < 3)

return year.substr(2);

else if (key > 4)

return setValue(Number(year), key);

else

return year;

}

case "M":

{

// month in year

var month:int = int(date.getMonth());

if (key < 3)

{

month++; // zero based

result += setValue(month, key);

return result;

}

else if (key == 3)

{

return DateBase.monthNamesShort[month];

}

else

{

return DateBase.monthNamesLong[month];

}

case "D":

{

// day in month

day = int(date.getDate());

result += setValue(day, key);

return result;

}

case "E":

{

// day in the week

day = int(date.getDay());

if (key < 3)

{

result += setValue(day, key);

return result;

}

else if (key == 3)

{

return DateBase.dayNamesShort[day];

}

else

{

return DateBase.dayNamesLong[day];

}

case "A":

{

// am/pm marker

hours = int(date.getHours());

if (hours < 12)

return DateBase.timeOfDay[0];

else

return DateBase.timeOfDay[1];

}

case "H":

{

// hour in day (1-24)

hours = int(date.getHours());

// if (hours == 0)

// hours = 24;

result += setValue(hours, key);

return result;

}

case "J":

{

// hour in day (0-23)

hours = int(date.getHours());

result += setValue(hours, key);

return result;

}

case "K":

{

// hour in am/pm (0-11)

hours = int(date.getHours());

if (hours >= 12)

hours = hours - 12;

result += setValue(hours, key);

return result;

}

case "L":

{

// hour in am/pm (1-12)

hours = int(date.getHours());

if (hours == 0)

hours = 12;

else if (hours > 12)

hours = hours - 12;

result += setValue(hours, key);

return result;

}

case "N":

{

// minutes in hour

var mins:int = int(date.getMinutes());

result += setValue(mins, key);

return result;

}

case "S":

{

// seconds in minute

var sec:int = int(date.getSeconds());

result += setValue(sec, key);

return result;

}

case "Q":

{

// milliseconds in second

var ms:int = int(date.getMilliseconds());

result += setValue(ms, key);

return result;

}

return result;

}

/**

* 重写format，解决将时间0:12:12格式化24:12:12问题

override public function format(value:Object):String

{

// Reset any previous errors.

if (error)

error = null;

// If value is null, or empty String just return ""

// but treat it as an error for consistency.

// Users will ignore it anyway.

if (!value || (value is String && value == ""))

{

error = defaultInvalidValueError;

return "";

}

// -- value --

if (value is String)

{

value = DateFormatter.parseDateString(String(value));

if (!value)

{

error = defaultInvalidValueError;

return "";

}

else if (!(value is Date))

{

error = defaultInvalidValueError;

return "";

}

// -- format --

var letter:String;

var nTokens:int = 0;

var tokens:String = "";

var n:int = formatString.length;

for (var i:int = 0; i < n; i++)

{

letter = formatString.charAt(i);

if (VALID_PATTERN_CHARS.indexOf(letter) != -1 && letter != ",")

{

nTokens++;

if (tokens.indexOf(letter) == -1)

{

tokens += letter;

}

else

{

if (letter != formatString.charAt(Math.max(i - 1, 0)))

{

error = defaultInvalidFormatError;

return "";

}

if (nTokens < 1)

{

error = defaultInvalidFormatError;

return "";

}

var dataFormatter:StringFormatterEX = new StringFormatterEX(

formatString, VALID_PATTERN_CHARS,

extractTokenDate);

return dataFormatter.formatValue(value);

}