Mysql
读取mysql表，中文乱码
在sql语句执行前执行mysql_query(&mysql, "SET NAMES GB2312");
mysql_query(&mysql, "SET NAMES GB2312");
写入中文到mysql表，中文乱码
在sql语句执行前执行mysql_query(&mysql, "SET NAMES UTF8");
mysql_query(&mysql, "SET NAMES UTF8");
URL
当 utf-8格式的url 数据转成字符串，用UrlDecode_UTF8
当 utf-8格式的string 字符串转成普通的std::string，用UTF8_To_string
反之使用string_To_UTF8和UrlEncode_UTF8
以下还提供GBK格式url的编码解码
Url：
byte toHex(const byte& x){return x > 9 ? x - 10 + 'A' : x + '0';}byte fromHex(const byte& x){return isdigit(x) ? x - '0' : x - 'A' + 10;}// URL解码，解码为GBKstd::string URLDecode(std::string strOrg){std::string sOut;for (size_t ix = 0; ix < strOrg.size(); ix++){byte ch = 0;if (strOrg[ix] == '%'){ch = (fromHex(strOrg[ix + 1]) << 4);ch |= fromHex(strOrg[ix + 2]);ix += 2;}else if (strOrg[ix] == '+'){ch = ' ';}else{ch = strOrg[ix];}sOut += (char)ch;}return sOut;}// URL编码，编码为GBKstd::string URLEncode(std::string strOrg){std::string sOut;for (size_t ix = 0; ix < strOrg.size(); ix++){byte buf[4];memset(buf, 0, 4);if (isalnum((byte)strOrg[ix])){buf[0] = strOrg[ix];}//else if ( isspace( (byte)strOrg[ix] ) ) //貌似把空格编码成%20或者+都可以 //{ // buf[0] = '+'; //} else{buf[0] = '%';buf[1] = toHex((byte)strOrg[ix] >> 4);buf[2] = toHex((byte)strOrg[ix] % 16);}sOut += (char*)buf;}return sOut;}std::string GBKToUTF8(const std::string strGBK){std::string strOutUTF8 = "";int n = MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, NULL, 0);wchar_t* str1 = new wchar_t[n];MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, str1, n);n = WideCharToMultiByte(CP_UTF8, 0, str1, -1, NULL, 0, NULL, NULL);char* str2 = new char[n];WideCharToMultiByte(CP_UTF8, 0, str1, -1, str2, n, NULL, NULL);strOutUTF8 = str2;delete[] str1;delete[] str2;return strOutUTF8;}std::string UTF8ToGBK(const std::string strUTF8){int len = MultiByteToWideChar(CP_UTF8, 0, strUTF8.c_str(), -1, NULL, 0);wchar_t* wszGBK = new wchar_t[len + 1];memset(wszGBK, 0, (len + 1) * sizeof(WCHAR));MultiByteToWideChar(CP_UTF8, 0, (LPCSTR)strUTF8.c_str(), -1, wszGBK, len);len = WideCharToMultiByte(CP_ACP, 0, wszGBK, -1, NULL, 0, NULL, NULL);char* szGBK = new char[len + 1];memset(szGBK, 0, len + 1);WideCharToMultiByte(CP_ACP, 0, wszGBK, -1, szGBK, len, NULL, NULL);//strUTF8 = szGBK;std::string strTemp(szGBK);delete[] szGBK;delete[] wszGBK;return strTemp;}// URL编码，编码为GBKstd::string UrlEncode_GBK(std::string strOrg){return URLEncode(strOrg);}// URL编码，编码为UTF-8std::string UrlEncode_UTF8(std::string strOrg){return URLEncode(GBKToUTF8(strOrg));}// URL解码，解码为GBKstd::string UrlDecode_GBK(std::string strOrg){return URLDecode(strOrg);}// URL解码，解码为UTF-8std::string UrlDecode_UTF8(std::string strOrg){return UTF8ToGBK(URLDecode(strOrg));}
std::string 和 utf-8 string 相互转换：
std::string string_To_UTF8(const std::string& str){int nwLen = ::MultiByteToWideChar(CP_ACP, 0, str.c_str(), -1, NULL, 0);wchar_t* pwBuf = new wchar_t[nwLen + 1];//一定要加1，不然会出现尾巴ZeroMemory(pwBuf, nwLen * 2 + 2);::MultiByteToWideChar(CP_ACP, 0, str.c_str(), str.length(), pwBuf, nwLen);int nLen = ::WideCharToMultiByte(CP_UTF8, 0, pwBuf, -1, NULL, NULL, NULL, NULL);char* pBuf = new char[nLen + 1];ZeroMemory(pBuf, nLen + 1);::WideCharToMultiByte(CP_UTF8, 0, pwBuf, nwLen, pBuf, nLen, NULL, NULL);std::string retStr(pBuf);delete[]pwBuf;delete[]pBuf;pwBuf = NULL;pBuf = NULL;return retStr;}std::string UTF8_To_string(const std::string& str){int nwLen = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), -1, NULL, 0);wchar_t* pwBuf = new wchar_t[nwLen + 1];//一定要加1，不然会出现尾巴memset(pwBuf, 0, nwLen * 2 + 2);MultiByteToWideChar(CP_UTF8, 0, str.c_str(), str.length(), pwBuf, nwLen);int nLen = WideCharToMultiByte(CP_ACP, 0, pwBuf, -1, NULL, NULL, NULL, NULL);char* pBuf = new char[nLen + 1];memset(pBuf, 0, nLen + 1);WideCharToMultiByte(CP_ACP, 0, pwBuf, nwLen, pBuf, nLen, NULL, NULL);std::string retStr = pBuf;delete[]pBuf;delete[]pwBuf;pBuf = NULL;pwBuf = NULL;return retStr;}
std::fstream
当fstream对象读取utf-8文件，先将文件内容从Utf-8转为Unicode，再写到std::wstring中，传到fstream内。
示例：
#include <fstream>// 读取Utf-8格式的文件，准备写入std::fstream ifile("path", std::ios::in | std::ios::out);std::string buffer;std::wstring wstr = L"";if (!ifile.is_open()){std::cout << "文件打开失败！" << std::endl;return -1;}while (std::getline(ifile, buffer)){wstr += tool.UTF8ToUnicode(buffer) + L'\n';}ifile.close();// wstring写入utf-8格式文件std::fstream ofile("path", std::ios::out);std::locale oldLocale1 = ofile.imbue(std::locale(std::locale("chs"), "", LC_CTYPE));if (!ofile.is_open()){std::cout << "文件打开失败！" << std::endl;return -1;}ofile << tool.ToUTF8(wstr );ofile.close();ofile.imbue(oldLocale1);
// 转码函数// 1std::string UnicodeToUTF8(const std::wstring& wstr){std::string ret;try {std::wstring_convert< std::codecvt_utf8<wchar_t> > wcv;ret = wcv.to_bytes(wstr);}catch (const std::exception& e) {std::string str = e.what();}return ret;}std::wstring UTF8ToUnicode(const std::string& str){std::wstring ret;try {std::wstring_convert< std::codecvt_utf8<wchar_t> > wcv;ret = wcv.from_bytes(str);}catch (const std::exception& e) {std::string str = e.what();}return ret;}std::string ToUTF8(const wchar_t* buffer, int len){int size = ::WideCharToMultiByte(CP_UTF8, 0, buffer, len, NULL, 0, NULL, NULL);if (size == 0)return "";std::string newbuffer;newbuffer.resize(size);::WideCharToMultiByte(CP_UTF8, 0, buffer, len,const_cast<char*>(newbuffer.c_str()), size, NULL, NULL);return newbuffer;}// 2std::string ToUTF8(const std::wstring& str){return ToUTF8(str.c_str(), (int)str.size());}
