在使用SQLite插入數據時出現亂碼的解決辦法

  在VC++中經過sqlite3.dll接口對sqlite數據庫進行操做，包括打開數據庫，插入，查詢數據庫等，若是操做接口輸入參數包含中文字符，會致使操做異常。例如調用sqlite3_open打開數據庫文件，若是文件路徑出現中文，就會致使打開失敗。sqlite3_exec執行sql語句，若是包含中文對應字符就會變成亂碼。

這是因爲sqlite數據庫使用的是UTF-8編碼方式，而傳入的字符串是ASCII編碼或Unicode編碼，致使字符串格式錯誤。解決方案是在調用sqlite接口以前，先將字符串轉換成UTF-8編碼，如下提供各類字符串編碼轉換函數。  

<pre name="code" class="cpp">//UTF-8轉Unicode 
std::wstring Utf82Unicode(const std::string& utf8string) 
{ 
int widesize = ::MultiByteToWideChar(CP_UTF8, 0, utf8string.c_str(), -1, NULL, 0); 
if (widesize == ERROR_NO_UNICODE_TRANSLATION) 
{ 
throw std::exception("Invalid UTF-8 sequence."); 
} 
if (widesize == 0) 
{ 
throw std::exception("Error in conversion."); 
} 
std::vector<wchar_t> resultstring(widesize); 
int convresult = ::MultiByteToWideChar(CP_UTF8, 0, utf8string.c_str(), -1, &resultstring[0], widesize); 
if (convresult != widesize) 
{ 
throw std::exception("La falla!"); 
} 
return std::wstring(&resultstring[0]); 
} 

//unicode 轉爲 ascii 
string WideByte2Acsi(wstring& wstrcode) 
{ 
int asciisize = ::WideCharToMultiByte(CP_OEMCP, 0, wstrcode.c_str(), -1, NULL, 0, NULL, NULL); 
if (asciisize == ERROR_NO_UNICODE_TRANSLATION) 
{ 
throw std::exception("Invalid UTF-8 sequence."); 
} 
if (asciisize == 0) 
{ 
throw std::exception("Error in conversion."); 
} 
std::vector<char> resultstring(asciisize); 
int convresult =::WideCharToMultiByte(CP_OEMCP, 0, wstrcode.c_str(), -1, &resultstring[0], asciisize, NULL, NULL); 
if (convresult != asciisize) 
{ 
throw std::exception("La falla!"); 
} 
return std::string(&resultstring[0]); 
} 

//utf-8 轉 ascii 
string UTF_82ASCII(string& strUtf8Code) 
{ 
string strRet(""); 
//先把 utf8 轉爲 unicode 
wstring wstr = Utf82Unicode(strUtf8Code); 
//最後把 unicode 轉爲 ascii 
strRet = WideByte2Acsi(wstr); 
return strRet; 
} 
/////////////////////////////////////////////////////////////////////// 
//

ascii 轉 Unicode 
wstring Acsi2WideByte(string& strascii) 
{ 
int widesize = MultiByteToWideChar (CP_ACP, 0, (char*)strascii.c_str(), -1, NULL, 0); 
if (widesize == ERROR_NO_UNICODE_TRANSLATION) 
{ 
throw std::exception("Invalid UTF-8 sequence."); 
} 
if (widesize == 0) 
{ 
throw std::exception("Error in conversion."); 
} 
std::vector<wchar_t> resultstring(widesize); 
int convresult = MultiByteToWideChar (CP_ACP, 0, (char*)strascii.c_str(), -1, &resultstring[0], widesize); 
if (convresult != widesize) 
{ 
throw std::exception("La falla!"); 
} 
return std::wstring(&resultstring[0]); 
} 

//Unicode 轉 Utf8 
std::string Unicode2Utf8(const std::wstring& widestring) 
{ 
int utf8size = ::WideCharToMultiByte(CP_UTF8, 0, widestring.c_str(), -1, NULL, 0, NULL, NULL); 
if (utf8size == 0) 
{ 
throw std::exception("Error in conversion."); 
} 
std::vector<char> resultstring(utf8size); 
int convresult = ::WideCharToMultiByte(CP_UTF8, 0, widestring.c_str(), -1, &resultstring[0], utf8size, NULL, NULL); 
if (convresult != utf8size) 
{ 
throw std::exception("La falla!"); 
} 
return std::string(&resultstring[0]); 
} 

//ascii 轉 Utf8 
string ASCII2UTF_8(string& strAsciiCode) 
{ 
string strRet(""); 
//先把 ascii 轉爲 unicode 
wstring wstr = Acsi2WideByte(strAsciiCode); 
//最後把 unicode 轉爲 utf8 
strRet = Unicode2Utf8(wstr); 
return strRet; 
}