Delphi读写UTF-8、Unicode格式文本文件

// UTF-8文件写入函数procedure SaveUTFFile(const FileName: string; S: string; WriteHeader: Boolean = True);varMemStream: TMemoryStream;HeaderStr: String;beginif S = '' then Exit; MemStream := TMemoryStream.Create;tryif WriteHeader thenbeginHeaderStr:=#$EF#$BB#$BF;MemStream.Write(HeaderStr[1],3);end; S := AnsiToUtf8(S);MemStream.Write(S[1],Length(S));MemStream.Position := 0; MemStream.SaveToFile(FileName);finallyMemStream.Free;end;end;// UtF-8文件读取函数function LoadUTFFile(const FileName: string; ReadHeader: Boolean = True): string;varMemStream: TMemoryStream;S,HeaderStr:string;beginResult:='';if not FileExists(FileName) then Exit;MemStream := TMemoryStream.Create;tryMemStream.LoadFromFile(FileName);if ReadHeader thenbeginSetLength(HeaderStr,3);MemStream.Read(HeaderStr[1],3); if HeaderStr = #$EF#$BB#$BF thenbeginSetLength(S,MemStream.Size - 3);MemStream.Read(S[1],MemStream.Size - 3);end;end elsebeginSetLength(S,MemStream.Size);MemStream.Read(S[1],MemStream.Size);end;Result := Utf8ToAnsi(S);finallyMemStream.Free;end;end;// Unicode文件写入函数procedure SaveUnicodeFile(const FileName:string; const S: string; WriteHeader: Boolean = True);varMemStream: TMemoryStream;HeaderStr: string;WStr: WideString;beginif S = '' then exit;MemStream := TMemoryStream.Create;tryif WriteHeader thenbeginHeaderStr := #$FF#$FE;MemStream.Write(HeaderStr[1],2);end;WStr := WideString(S);MemStream.Write(WStr[1],Length(WStr)*2);MemStream.Position := 0;MemStream.SaveToFile(FileName);finallyMemStream.Free;end;end;// Unicode文件读取函数function LoadUnicodeFile(const FileName: string; ReadHeader: Boolean = True): string;varMemStream: TMemoryStream;FlagStr: String;WStr: WideString;beginResult := '';if not FileExists(FileName) then Exit;MemStream := TMemoryStream.Create;tryMemStream.LoadFromFile(FileName); if ReadHeader thenbeginSetLength(FlagStr,2);MemStream.Read(FlagStr[1],2);if FlagStr = #$FF#$FE thenbeginSetLength(WStr,(MemStream.Size-2) div 2);MemStream.Read(WStr[1],MemStream.Size - 2);end;end elsebeginSetLength(WStr,MemStream.Size div 2);MemStream.Read(WStr[1],MemStream.Size);end;Result := AnsiString(WStr);finallyMemStream.Free;end;end;//保存文件procedure savetofile(const FileName:string; const S: string);varF: TextFile;beginAssignFile(F,FileName); // 将文件与F变量建立连接，后面可以使用F变量对文件进行操作。Rewrite(F); // 以追加的方式打开文件Writeln(F,S); // 将S变量中的内容追加到文本尾后。CloseFile(F); // 关闭文件end