sqlite中文乱码问题原因分析及解决

在VC++中通过sqlite3.dll接口对sqlite数据库进行操作，包括打开数据库，插入，查询数据库等，如果操作接口输入参数包含中文字符，会导致操作异常。例如调用sqlite3_open打开数据库文件，如果文件路径出现中文，就会导致打开失败。sqlite3_exec执行sql语句，如果包含中文对应字符就会变成乱码。
    这是由于sqlite数据库使用的是UTF-8编码方式，而传入的字符串是ASCII编码或Unicode编码，导致字符串格式错误。解决方案是在调用sqlite接口之前，先将字符串转换成UTF-8编码，以下提供各种字符串编码转换函数。
    复制代码 代码如下:
    
    //UTF-8转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 转为 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 转 ascii
    string UTF_82ASCII(string& strUtf8Code)
    {
    string strRet("");
    //先把 utf8 转为 unicode
    wstring wstr = Utf82Unicode(strUtf8Code);
    //最后把 unicode 转为 ascii
    strRet = WideByte2Acsi(wstr);
    return strRet;
    }
    ///////////////////////////////////////////////////////////////////////
    //ascii 转 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 转 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 转 Utf8
    string ASCII2UTF_8(string& strAsciiCode)
    {
    string strRet("");
    //先把 ascii 转为 unicode
    wstring wstr = Acsi2WideByte(strAsciiCode);
    //最后把 unicode 转为 utf8
    strRet = Unicode2Utf8(wstr);
    return strRet;
    }