發(fā)現(xiàn)開源代碼的可利用資源真多，從sqlite3的源碼中摳出了幾個字符轉(zhuǎn)換接口，稍微改造下了發(fā)現(xiàn)還挺好用的。下面是實現(xiàn)代碼：

/*
**?Convert?a?UTF-8?string?to?microsoft?unicode?(UTF-16?).?
**
**?Space?to?hold?the?returned?string?is?obtained?from?malloc.
*/
static?WCHAR?*utf8ToUnicode(const?char?*zFilename){

	int?nChar;
	WCHAR?*zWideFilename;

	nChar?=?MultiByteToWideChar(CP_UTF8,?0,?zFilename,?-1,?NULL,?0);
	zWideFilename?=?static_cast(malloc(nChar*sizeof(zWideFilename[0])));
	if(?zWideFilename==0?){

		return?0;

	}
	nChar?=?MultiByteToWideChar(CP_UTF8,?0,?zFilename,?-1,?zWideFilename,?nChar);
	if(?nChar==0?){

		free(zWideFilename);
		zWideFilename?=?0;

	}
	return?zWideFilename;

}

/*
**?Convert?microsoft?unicode?to?UTF-8.??Space?to?hold?the?returned?string?is
**?obtained?from?malloc().
*/
static?char?*unicodeToUtf8(const?WCHAR?*zWideFilename){

	int?nByte;
	char?*zFilename;

	nByte?=?WideCharToMultiByte(CP_UTF8,?0,?zWideFilename,?-1,?0,?0,?0,?0);
	zFilename?=?static_cast(malloc(?nByte?));
	if(?zFilename==0?){

		return?0;

	}
	nByte?=?WideCharToMultiByte(CP_UTF8,?0,?zWideFilename,?-1,?zFilename,?nByte,
		0,?0);
	if(?nByte?==?0?)
	{
		free(zFilename);
		zFilename?=?0;
	}
	return?zFilename;

}

/*
**?Convert?an?ansi?string?to?microsoft?unicode,?based?on?the
**?current?codepage?settings?for?file?apis.
**?
**?Space?to?hold?the?returned?string?is?obtained
**?from?malloc.
*/
static?WCHAR?*mbcsToUnicode(const?char?*zFilename){

	int?nByte;
	WCHAR?*zMbcsFilename;
	int?codepage?=?AreFileApisANSI()???CP_ACP?:?CP_OEMCP;

	nByte?=?MultiByteToWideChar(codepage,?0,?zFilename,?-1,?NULL,0)*sizeof(WCHAR);
	zMbcsFilename?=?static_cast(malloc(?nByte*sizeof(zMbcsFilename[0])));
	if(?zMbcsFilename==0?){

		return?0;

	}
	nByte?=?MultiByteToWideChar(codepage,?0,?zFilename,?-1,?zMbcsFilename,?nByte);
	if(?nByte==0?)
	{
		free(zMbcsFilename);
		zMbcsFilename?=?0;
	}
	return?zMbcsFilename;

}

/*
**?Convert?microsoft?unicode?to?multibyte?character?string,?based?on?the
**?user's?Ansi?codepage.
**
**?Space?to?hold?the?returned?string?is?obtained?from
**?malloc().
*/
static?char*?unicodeToMbcs(const?WCHAR*?zWideFilename){

	int?nByte;
	char?*zFilename;
	int?codepage?=?AreFileApisANSI()???CP_ACP?:?CP_OEMCP;

	nByte?=?WideCharToMultiByte(codepage,?0,?zWideFilename,?-1,?0,?0,?0,?0);
	zFilename?=?static_cast(malloc(nByte?));
	if(?zFilename==0?){

		return?0;

	}
	nByte?=?WideCharToMultiByte(codepage,?0,?zWideFilename,?-1,?zFilename,?nByte,
		0,?0);
	if(?nByte?==?0?){

		free(zFilename);
		zFilename?=?0;
	}
	return?zFilename;

}

/*
**?Convert?multibyte?character?string?to?UTF-8.??Space?to?hold?the
**?returned?string?is?obtained?from?malloc().
*/
static?char*?mbcsToUtf8(const?char?*zFilename){

	char?*zFilenameUtf8;
	WCHAR?*zTmpWide;

	zTmpWide?=?mbcsToUnicode(zFilename);
	if(?zTmpWide==0?){

		return?0;

	}
	zFilenameUtf8?=?unicodeToUtf8(zTmpWide);
	free(zTmpWide);
	return?zFilenameUtf8;
}

/*
**?Convert?UTF-8?to?multibyte?character?string.??Space?to?hold?the?
**?returned?string?is?obtained?from?malloc().
*/
static?char*?utf8ToMbcs(const?char?*zFilename){

	char?*zFilenameMbcs;
	WCHAR*?zTmpWide;

	zTmpWide?=?utf8ToUnicode(zFilename);
	if(?zTmpWide==0?){

		return?0;

	}
	zFilenameMbcs?=?unicodeToMbcs(zTmpWide);
	free(zTmpWide);
	return?zFilenameMbcs;
}

std::string?MbcsToUtf8(?const?char*?pszMbcs?)
{
	std::string?str;
	WCHAR???*pwchar=0;
	CHAR????*pchar=0;
	int?len=0;
	int?codepage?=?AreFileApisANSI()???CP_ACP?:?CP_OEMCP;
	len=MultiByteToWideChar(codepage,?0,?pszMbcs,?-1,?NULL,0);
	pwchar=new?WCHAR[len];
	if(pwchar!=0)
	{
		len?=?MultiByteToWideChar(codepage,?0,?pszMbcs,?-1,?pwchar,?len);
		if(?len!=0?)
		{
			len?=?WideCharToMultiByte(CP_UTF8,?0,?pwchar,?-1,?0,?0,?0,?0);
			pchar=new?CHAR[len];
			if(pchar!=0)
			{
				len?=?WideCharToMultiByte(CP_UTF8,?0,?pwchar,?-1,?pchar,?len,0,?0);
				if(len!=0)????????????????
				{
					str?=?pchar;???????????????????
				}
				delete?pchar;
			}
			delete?pwchar;
		}
	}
	return?str;
}

????

? ?????? 要測試這些接口，為此我寫了一個測試工程，是讀取一個xml文件把里面的字符進(jìn)行轉(zhuǎn)換的，測試工程的代碼下載地址如下：

unicode字符和多字節(jié)字符的相互轉(zhuǎn)換接口及測試工程