{
在delphi中没有能把字符串直接保存为文件的方法，也没有将文件直接作为字符串读出的方法。
没有能把字符串转化为内存流的方法，也没有能把内存流转化为字符串的方法。而这里有四个函数恰能做到。
代码如下：
}
function StringToFile(mString: string; mFileName: TFileName): Boolean;
{ 返回字符串保存到文件是否成功 }
var
vFileChar: file of Char;//通常是以行为单位，将依次写入每一行，而这里是字，则将依次写入每个字
I: Integer;
begin
{$I-}
AssignFile(vFileChar, mFileName);
Rewrite(vFileChar);
for I := 1 to Length(mString) do
Write(vFileChar, mString[I]);
CloseFile(vFileChar);
{$I+}
Result := (IOResult = 0) and (mFileName <> '');
end; { StringToFile }
function FileToString(mFileName: TFileName): string;
{ 返回从文件载入字符串 }
var
vFileChar: file of Char;
vChar: Char;
begin
Result := '';
{$I-}
AssignFile(vFileChar, mFileName);
Reset(vFileChar);
while not Eof(vFileChar) do begin
Read(vFileChar, vChar);
Result := Result + vChar;
end;
CloseFile(vFileChar);
{$I+}
end; { FileToString }
function AnsiFileToString(mFileName: TFileName): Ansistring; //返回从文件载入字符串 }
var
vFileChar: file of AnsiChar;
vChar: AnsiChar;
begin
Result := '';
{$I-}
AssignFile(vFileChar, mFileName);
Reset(vFileChar);
while not Eof(vFileChar) do begin
Read(vFileChar, vChar);
Result := Result + vChar;
end;
CloseFile(vFileChar);
{$I+}
end; { AnsiFileToString }
function StreamToString(mStream: TStream): string;
{ 将内存流转换成字符串 }
var
I: Integer;
begin
Result := '';
if not Assigned(mStream) then Exit;
SetLength(Result, mStream.Size);
for I := 0 to Pred(mStream.Size) do try
mStream.Position := I;
mStream.Read(Result[Succ(I)], 1);
except
Result := '';
end;
end; { StreamToString }
function StringToStream(mString: string; mStream: TStream): Boolean;
{ 返回将字符串保存到内存流是否成功 }
var
I: Integer;
begin
Result := True;
try
mStream.Size := 0;
mStream.Position := 0;
for I := 1 to Length(mString) do mStream.Write(mString[I], 1);
except
Result := False;
end;
end; { StringToStream }
//一个把字符转换成各种编码文件的delphi2010函数.
procedure SaveFile( const FileName: string ; Source: string ;
encoding: TEncoding);
var
sl: TStrings;
memoStream: TFileStream;
buff: Tbytes;
LByteOrderMark: TBytes;
begin
if Source = ' ' then
exit ;
try
buff : = encoding.GetBytes(Source);
memoStream : = TFileStream.Create(FileName, fmCreate);
LByteOrderMark : = encoding.GetPreamble;
memoStream.Write(LByteOrderMark[ 0 ], Length(LByteOrderMark));
memoStream.Write(buff[ 0 ], length(buff));
memostream.s
finally
memoStream.Free;
end ;
end ;
{SaveFile('C:Temp est_' + 'ascii_gbk.txt', ss, TEncoding.GetEncoding(936));//gbk
SaveFile('C:Temp est_' + 'ascii_bg5.txt', ss, TEncoding.GetEncoding(950));//bg5 繁体
SaveFile('C:Temp est_' + 'utf8.txt', ss, TEncoding.UTF8);
SaveFile('C:Temp est_' + 'unicode.txt', ss, TEncoding.Unicode);
unicode转中文的时候必须要制定页码,不然会出现乱码.比如的以下这两句.
SaveFile('C:Temp est_' + 'ascii_gbk.txt', ss, TEncoding.GetEncoding(936));//gbk
SaveFile('C:Temp est_' + 'ascii_bg5.txt', ss, TEncoding.GetEncoding(950));//bg5 繁体}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
unit util_utf8;
interface
uses Windows;
type
UTF8String = AnsiString;
function AnsiToWide(const S: AnsiString): WideString;
function WideToUTF8(const WS: WideString): UTF8String;
function AnsiToUTF8(const S: AnsiString): UTF8String;
function UTF8ToWide(const US: UTF8String): WideString;
function WideToAnsi(const WS: WideString): AnsiString;
function UTF8ToAnsi(const S: UTF8String): AnsiString;
implementation
function AnsiToWide(const S: AnsiString): WideString;
var len: integer;
ws: WideString;
begin
Result:='';
if (Length(S) = 0) then
exit;
len:=MultiByteToWideChar(CP_ACP, 0, PChar(s), -1, nil, 0);
SetLength(ws, len);
MultiByteToWideChar(CP_ACP, 0, PChar(s), -1, PWideChar(ws), len);
Result:=ws;
end;
function WideToUTF8(const WS: WideString): UTF8String;
var len: integer;
us: UTF8String;
begin
Result:='';
if (Length(WS) = 0) then
exit;
len:=WideCharToMultiByte(CP_UTF8, 0, PWideChar(WS), -1, nil, 0, nil, nil);
SetLength(us, len);
WideCharToMultiByte(CP_UTF8, 0, PWideChar(WS), -1, PChar(us), len, nil, nil);
Result:=us;
end;
function AnsiToUTF8(const S: AnsiString): UTF8String;
begin
Result:=WideToUTF8(AnsiToWide(S));
end;
function UTF8ToWide(const US: UTF8String): WideString;
var len: integer;
ws: WideString;
begin
Result:='';
if (Length(US) = 0) then
exit;
len:=MultiByteToWideChar(CP_UTF8, 0, PChar(US), -1, nil, 0);
SetLength(ws, len);
MultiByteToWideChar(CP_UTF8, 0, PChar(US), -1, PWideChar(ws), len);
Result:=ws;
end;
function WideToAnsi(const WS: WideString): AnsiString;
var len: integer;
s: AnsiString;
begin
Result:='';
if (Length(WS) = 0) then
exit;
len:=WideCharToMultiByte(CP_ACP, 0, PWideChar(WS), -1, nil, 0, nil, nil);
SetLength(s, len);
WideCharToMultiByte(CP_ACP, 0, PWideChar(WS), -1, PChar(s), len, nil, nil);
Result:=s;
end;
function UTF8ToAnsi(const S: UTF8String): AnsiString;
begin
Result:=WideToAnsi(UTF8ToWide(S));
end;
end.