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，输出的结果会自己主动换行。默觉得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);;

		}

	}