German Umlaute 的问题，从 SWI Prolog 到 JAVA 的 TCPIP

Question

我尝试在 Prolog 服务器应用程序和 Java 客户端应用程序之间实现 tcpip 连接。它有效，但我有一个问题，我没有正确收到德语变音符号（ä、ü 等）。这就是我所做的：

在Java，客户端：

inputreader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream(),"UTF-8" ));

...

StringBuilder sb = new StringBuilder();
String responseLine;
while ((responseLine = inputreader.readLine()) != null) {
    // System.out.println("Server: " + responseLine);

    // Character.toString ((char) i);
    sb.append(responseLine);
    if( responseLine.indexOf( ".") != -1 && responseLine.length() == 1 ){
       break;
    }
}

在 SWI Prolog 中，服务器端：

:- set_prolog_flag(encoding,utf8).

% based on http://swi-prolog.996271.n3.nabble.com/socket-communication-td1653.html
server(PortNumber) :-
    setup_call_cleanup(tcp_socket(S),  % no leaks, please
           (true; fail),
           tcp_close_socket(S)),
    tcp_bind(S, PortNumber),
    tcp_listen(S, 5),
    format('listen to portnumber ~w~n', [PortNumber]),
    server_loop(S).

server_loop(S) :-
    tcp_accept(S, S1, From),
    format('receiving traffic from: ~q~n', [From]),
    setup_call_cleanup(tcp_open_socket(S1, In, Out),
           server_operation(In, Out),
           (  writeln('closing...'),
              close(In),
              close(Out))), !,
    server_loop(S).

server_operation(In, Out) :-
    \+at_end_of_stream(In),
    read_pending_input(In, Codes, []), 
    atom_codes(Text,Codes),
    write('received from client: '),write(Text),nl,

    % job which has to be done in Prolog
    extract_fct_call( Text, Fname, ListOfIname, ListOfIcontent ),
    call_fct( Fname, ListOfIname, ListOfIcontent, XMLreply ),

    atom_codes( XMLreply, CodeReply ),
    % append defined EOM as \n.\n
    append( CodeReply, [10,46,10], CodeMessage ),
    format(Out, '~s', [Message]),
    flush_output(Out),
    server_operation(In, Out).

server_operation(_In, _Out).

所以，我认为定义双方 UTF-8 编码就可以了，但事实并非如此。我在 "Gemüse" 的 SWI Prolog 端开始并在 Java 端接收 "Gemxse"。我尝试使用

发送 ASCII 码

atom_codes( Message, CodeMessage ),
format(Out, '~s', [CodeMessage]),

和Java一侧

inputreader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream(),"US-ASCII" ));

或

inputreader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream(),"ASCII" ));

但结果没有改变。我能做什么？

非常感谢！

解决方案：

在 CapelliC 的帮助下，通过添加

解决了这个问题

set_stream(流，编码(utf8))

到

server_operation(In, Out) :-
    set_stream(In, encoding(utf8)),
    set_stream(Out, encoding(utf8)),
    \+at_end_of_stream(In),
    ...

然后在 Java 应用程序中接收到变音符号（确保在项目的属性中，文本的编码也设置为 UTF-8）。

Answer 1

stream_property(Stream, encoding(Encoding)) 将允许您检查和更改 Prolog 端的编码。但是一旦你确认 Prolog 实际上默认为 UTF-8，并且你对此感到满意，也许你应该调整 Java 接口，也许在每个 IO 操作上指定编码

byte[] utf8Bytes = s.getBytes("UTF-8");

German Umlaute 的问题，从 SWI Prolog 到 JAVA 的 TCPIP

Problems with German Umlaute, TCPIP from SWI Prolog to JAVA

java

prolog

tcp-ip

ffi

swi-prolog