Flex/AS3 base64指定字符编码

public static function base64Encode(str:String, charset:String = "GBK"):String{if(StringUtils.getInstance().isEmpty(str)){return "";}var base64:Base64Encoder = new Base64Encoder();base64.insertNewLines = false;//该值等于true时，输出的结果会自动换行，默认为true  var byte:ByteArray = new ByteArray();byte.writeMultiByte(str, charset);base64.encodeBytes(byte);return base64.toString();}public static function base64Decode(str:String, charset:String = "GBK"):String{if(StringUtils.getInstance().isEmpty(str)){return "";}var base64:Base64Decoder = new Base64Decoder();base64.decode(str);var byteArray:ByteArray = base64.toByteArray();return byteArray.readMultiByte(byteArray.length, charset);;}}