Flex识别文本文件编码

private function butClickHandle(e:MouseEvent):void
??? {
???? var file:File = File.desktopDirectory;??
????//打开文件
???? if (e.target.id=="but_openfile"){
????? var txtfilter:FileFilter = new FileFilter("Text","*.as;*.css;*.txt;*.java;*.html;*.htm;*.xml");
????? file.browseForOpen("Open",[txtfilter]);
????? file.addEventListener(Event.SELECT,function(e:Event):void{
?????? var file:File = new File(e.target.nativePath);
?????? var filestream:FileStream = new FileStream;
?????? filestream.open(file,FileMode.READ);
?????? var bytes:ByteArray = new ByteArray;
?????? filestream.readBytes(bytes,file.size);
?????? txtfile.text = transEncodingText(bytes);
????? });?
???? }
????//打开文件夹
???? if (e.target.id=="but_opendir"){
????? file.browseForDirectory("打开文件夹");
????? file.addEventListener(Event.SELECT,function(e:Event):void{
?????? txtfile.text = e.target.nativePath + File.lineEnding;
?????? var contents:Array = File(e.target).getDirectoryListing();
?????? for (var i:int=0;i<contents.length;i++){
??????? txtfile.text += contents[i].name +"t"+ contents[i].size + File.lineEnding;?
?????? }
????? });??
???? }
??? }

//var bytes:ByteArray = new ByteArray;
//filestream.readBytes(bytes,file.size);
// 读取不同 编码的文档
??? private function transEncodingText(bytes:ByteArray):String
??? {
?????// 1. unicode 文档 开头 16进制码为 FF FE,对应 十进制 数 为 255，254
???? if (bytes[0]==255 && bytes[1]==254){
????? return bytes.readMultiByte(bytes.length,"unicode");
???? }?
?????// 2.unicode big endian 开头 16进制 为 FE FF，对应十进制数 为 254，255
???? if (bytes[0]==254 && bytes[1]==255){
????? return bytes.readMultiByte(bytes.length,"UTF-16BE");
???? }
????// 3.utf-8 开头 16进制 为 EF BB ，对应 十进制 数 为 239，187
???? if (bytes[0]==239 && bytes[1]==187){
????? return bytes.readMultiByte(bytes.length,"utf-8");
???? }
?????// 默认采用系统编码 读取 ???? return bytes.readMultiByte(bytes.length,File.systemCharset); ??? }