//字节数组转换为HEX 字符串
const string Byte2HexString(const unsigned char* input, const int datasize)

{

    char  output[datasize*];

    for(int j = ; j < datasize; j++ )

    {

        unsigned char b = *(input+j);

        snprintf( output+j * ,, "%02x",b);

    }

    return string(output) ;

}

/*

* 把16进制字符串转换成字节数组 @param hex @return

*/

unsigned char* HexString2Byte(string hex)

{

    int len = (hex.length() / );

    unsigned char* result = new unsigned char[len];

    //const char* achar = hex.c_str();

    for (int i = ; i < len; i++) {

        int pos = i * ;

        QString lStr(hex[pos]);

        int iLeft = lStr.toInt(NULL, );

        QString rStr(hex[pos+]);

        int iRight = rStr.toInt(NULL, );

        int iNew = ( iLeft<<  | iRight);

        result[i] = (unsigned char) iNew;

    }

    return result;

}

BYTE face_feature[];

//16进制字符串转换为字节数组

unsigned char* pFeature = HexString2Byte(strFeature);

    memcpy(face_feature, pFeature, strFeature.length()/);

//字节数组转换为16进制字符串

string strFeature = Byte2HexString(face_feature,);