如果您对UTF-8、Unicode、GB2312等还是很陌生话请查看http://www.linuxforum.net/books/UTF-8-Unicode.html我这里就不浪费口舌了下面介绍下WinAPI两个:WideCharToMultiByte、MultiByteToWideChar

原型:
WideCharToMultiByte(
UINTCodePage,//codepage
DWORDdwFlags,//performanceandmappingflags
LPCWSTRlpWideCharStr,//wide-character
cchWideChar,//numberofcharsin
LPSTRlpMultiByteStr,//bufferfor
cbMultiByte,//buffer
LPCSTRlpDefaultChar,//defaultforunmappablechars
LPBOOLlpUsedDefaultChar//whendefaultcharused
);//将宽转换成多个窄

MultiByteToWideChar(
UINTCodePage,//codepage
DWORDdwFlags,//character-typeoptions
LPCSTRlpMultiByteStr,//tomap
cbMultiByte,//numberofsin
LPWSTRlpWideCharStr,//wide-characterbuffer
cchWideChar//buffer
);//将多个窄转换成宽
需要用到些:
CStringCXmlProcess::HexToBin(CString)//将16进制数转换成2进制
{
(\"0\")\"0000\";
(\"1\")\"0001\";
(\"2\")\"0010\";
(\"3\")\"0011\";
(\"4\")\"0100\";
(\"5\")\"0101\";
(\"6\")\"0110\";
(\"7\")\"0111\";
(\"8\")\"1000\";
(\"9\")\"1001\";
(\"a\")\"1010\";
(\"b\")\"1011\";
(\"c\")\"1100\";
(\"d\")\"1101\";
(\"e\")\"1110\";
(\"f\")\"1111\";
\"\";
}


CStringCXmlProcess::BinToHex(CStringBinString)//将2进制数转换成16进制
{
(BinString\"0000\")\"0\"; [Page]
(BinString\"0001\")\"1\";
(BinString\"0010\")\"2\";
(BinString\"0011\")\"3\";
(BinString\"0100\")\"4\";
(BinString\"0101\")\"5\";
(BinString\"0110\")\"6\";
(BinString\"0111\")\"7\";
(BinString\"1000\")\"8\";
(BinString\"1001\")\"9\";
(BinString\"1010\")\"a\";
(BinString\"1011\")\"b\";
(BinString\"1100\")\"c\";
(BinString\"1101\")\"d\";
(BinString\"1110\")\"e\";
(BinString\"1111\")\"f\";
\"\";
}

CXmlProcess::BinToInt(CString)//2进制数据转换成10进制整型
{
len=0;
tempInt=0;
strInt=0;
for(i=0;i<.GetLength;i)
{
tempInt=1;
strInt=().GetAt(i)-48;
for(k=0;k<7-i;k)
{
tempInt=2*tempInt;
}
lentempInt*strInt;
}
len;
}


　　UTF-8转换成GB2312先把UTF-8转换成Unicode.然后再把Unicode通过WideCharToMultiByte转换成GB2312
WCHAR*CXmlProcess::UTF_8ToUnicode(char*ustart)//把UTF-8转换成Unicode
{
charchar_one;
charchar_two;
charchar_three;
Hchar;
Lchar;
charuchar[2];
WCHAR*unicode;
CString_one;
CString_two;
CString_three;
CStringcombiString;
char_one=*ustart;
char_two=*(ustart+1); [Page]
char_three=*(ustart+2);
_one.Format(\"%x\",char_one);
_two.Format(\"%x\",char_two);
_three.Format(\"%x\",char_three);
_three=_three.Right(2);
_two=_two.Right(2);
_one=_one.Right(2);
_three=HexToBin(_three.Left(1))+HexToBin(_three.Right(1));
_two=HexToBin(_two.Left(1))+HexToBin(_two.Right(1));
_one=HexToBin(_one.Left(1))+HexToBin(_one.Right(1));
combiString=_one+_two+_three;
combiString=combiString.Right(20);
combiString.Delete(4,2);
combiString.Delete(10,2);
Hchar=BinToInt(combiString.Left(8));
Lchar=BinToInt(combiString.Right(8));
uchar[1]=(char)Hchar;
uchar[0]=(char)Lchar;
unicode=(WCHAR*)uchar;
unicode;
}

char*CXmlProcess::UnicodeToGB2312(unsigneduData)//把Unicode转换成GB2312
{
char*buffer;
buffer=char[(WCHAR)];
WideCharToMultiByte(CP_ACP,NULL,&uData,1,buffer,(WCHAR),NULL,NULL);
buffer;
}
　　GB2312转换成UTF-8:先把GB2312通过MultiByteToWideChar转换成Unicode.然后再把Unicode通过拆开Unicode后拼装成UTF-8
WCHAR*CXmlProcess::Gb2312ToUnicode(char*gbBuffer)//GB2312转换成　Unicode
{
WCHAR*uniChar;
uniChar=WCHAR[1];
::MultiByteToWideChar(CP_ACP,MB_PRECOMPOSED,gbBuffer,2,uniChar,1);
uniChar;
}
char*CXmlProcess::UnicodeToUTF_8(WCHAR*UniChar)//Unicode转换成UTF-8
{
char*buffer;
CStringstrOne;
CStringstrTwo;
CStringstrThree;
CStringstrFour;
CStringstrAnd;
buffer=char[3];
hInt,lInt;
hInt=()((*UniChar)/256);
lInt=(*UniChar)%256;
CString;
.Format(\"%x\",hInt);
strTwo=HexToBin(.Right(1));
=.Left(.GetLength-1);
strOne=HexToBin(.Right(1));
.Format(\"%x\",lInt); [Page]
strFour=HexToBin(.Right(1));
=.Left(.GetLength-1);
strThree=HexToBin(.Right(1));
strAnd=strOne+strTwo+strThree+strFour;
strAnd.Insert(0,\"1110\");
strAnd.Insert(8,\"10\");
strAnd.Insert(16,\"10\");
strOne=strAnd.Left(8);
strAnd=strAnd.Right(16);
strTwo=strAnd.Left(8);
strThree=strAnd.Right(8);
*buffer=(char)BinToInt(strOne);
buffer[1]=(char)BinToInt(strTwo);
buffer[2]=(char)BinToInt(strThree);
buffer;
}
例子:将GB2312转换成UTF-8:
char*CXmlProcess::translateCharToUTF_8(char*xmlStream,len)
{
CharLen=0;
oldCharLen=0;
revCharLen=len;
char*CharBuffer;
char*finalCharBuffer;
char*buffer;
CString;
buffer=char[(WCHAR)];
CharBuffer=char[(1.5*revCharLen)];//设置最大个缓冲区
while(oldCharLen<revCharLen)
{
(*(xmlStream+oldCharLen)>=0)
{
*(CharBuffer+CharLen)=*(xmlStream+oldCharLen);
CharLen;
oldCharLen;


}//如果是英文直接复制就可以

{
WCHAR*pbuffer=this->Gb2312ToUnicode(xmlStream+oldCharLen);
buffer=this->UnicodeToUTF_8(pbuffer);
*(CharBuffer+CharLen)=*buffer;
*(CharBuffer+CharLen+1)=*(buffer+1);
*(CharBuffer+CharLen+2)=*(buffer+2);
CharLen3;
oldCharLen2;
}
}
CharBuffer[CharLen]=’’\\0’’;
CString1;
1.Format(\"%s\",CharBuffer);
finalCharBuffer=char[CharLen+1];
memcpy(finalCharBuffer,CharBuffer,CharLen+1);
finalCharBuffer;
}