How to send text in UTF-8 using Indy TIdTCPServer in c++ builder

My client j2me application reading text input stream using UTF-8

reader = new InputStreamReader(in,"UTF-8");

and my server when gets connected sends text using this statement

AContext->Connection->IOHandler->WriteLn(cxMemo1->Text,TEncoding::UTF8);

but result text showing weird characters like ?????????????????????????? ?????????????

Where I'm doing wrong?

also when i tried to load from 开发者_Python百科utf-8 encoding data file in such a way

AContext->Connection->IOHandler->WriteFile("c:\\fids.xml");

it's all the same!

Indy 10 completely supports UTF-8 encoding. I've myself worked with it's TIdFTP component & successfully uploaded Unicode text files. From what I can make of it:

1. Your connection/transfer type is set to ftASCII rather than ftBinary.
2. Your J2ME applet/Host platform does not suport UTF-8

'?' characters occur when data is going through a Unicode-to-Ansi conversion to an Ansi charset that does not support the Unicode characters being converted.

What version of C++Builder are you using? In versions prior to CB2009, you should tell Indy the encoding of the AnsiString data that you are passing in. Indy defaults to ASCII (ie: TIdTextEncoding::ASCII) for most String-based operation. That can be overridden when needed, either with optional AAnsiEncoding parameters, the TIdIOHandler::DefAnsiEncoding property, or the global Idglobal::GIdDefaultAnsiEncoding setting. If you do not specify the correct encoding, the AnsiString data may not be converted to Unicode correctly before then being converted to UTF-8. For example:

AContext->Connection->IOHandler->WriteLn(cxMemo1->Text, TIdTextEncoding_UTF8, TTIdTextEncoding_Default);

Or:

AContext->Connection->IOHandler->DefAnsiEncoding = TIdTextEncoding_Default;
AContext->Connection->IOHandler->WriteLn(cxMemo1->Text, TIdTextEncoding_UTF8);

You can optionally also use the TIdIOHandler::DefStringEncoding property if you do not want to specify the UTF-8 encoding on every call:

AContext->Connection->IOHandler->DefStringEncoding = TIdTextEncoding_UTF8;
AContext->Connection->IOHandler->WriteLn(cxMemo1->Text);

Now, with that said, the fact that WriteFile() is also sending data that J2ME is not handling correctly tells me that Indy is not the root of the issue. WriteFile() simply dups the raw file data as-is to the connection without any interpretation at all. If you send a UTF-8 encoded file, then UTF-8 encoded octets will be sent to J2ME.

I suggest you use a packet sniffer, such as Wireshark, to verify the data that Indy is sending. That will tell you for sure whether Indy is really at fault or not.

*PS: notice in the examples above that I use Indy's TIdTextEncoding macros instead of TEncoding directly. This is because Indy's TIdTextEncoding logic works around some bugs in Embarcadero's TEncoding classes. Also, we're going to phase out direct support for TEncoding in Indy 11 and expand on TIdTextEncoding so Indy has more control than Embarcadero offers.