Roman numerals to integers

Question

I have a transfer with products that unfortunately has to get matched by product name. The biggest issue here is I might get duplicate products on account of roman numbers.

Answer 1

private static HashMap<Character, Integer> romanMap = new HashMap<>() {{
    put('I', 1); put('V', 5); put('X', 10); put('L', 50); 
    put('C', 100); put('D', 500); put('M', 1000);
}};

private static int convertRomanToInt(String romanNumeral) {
    int total = 0;
    romanNumeral = romanNumeral.toUpperCase();

    //add every Roman numeral
    for(int i = 0; i < romanNumeral.length(); i++) {
        total += romanMap.get(romanNumeral.charAt(i));
    }

    //remove the Roman numerals that are followed 
    //directly by a larger Roman numeral
    for(int i = 0; i < romanNumeral.length()-1; i++) {
        if(romanMap.get(romanNumeral.charAt(i)) 
           < romanMap.get(romanNumeral.charAt(i+1))) {
           total -= 2* romanMap.get(romanNumeral.charAt(i));
        }
    }
    return total;
}

//note that the topmost solution does not solve this Roman numeral
//but mine does
//also note that this solution is a preference of simplicity over complexity
public static void main(String[] args) {
    String rn = "CcLXxiV"; //274
    System.out.println("Convert " + rn + " to " + convertRomanToInt(rn));
}

Answer 2

public static int ConvertRomanNumtoInt(string strRomanValue)
{
    Dictionary RomanNumbers = new Dictionary
    {
        {"M", 1000},
        {"CM", 900},
        {"D", 500},
        {"CD", 400},
        {"C", 100},
        {"XC", 90},
        {"L", 50},
        {"XL", 40},
        {"X", 10},
        {"IX", 9},
        {"V", 5},
        {"IV", 4},
        {"I", 1}
    };
    int retVal = 0;
    foreach (KeyValuePair pair in RomanNumbers)
    {
        while (strRomanValue.IndexOf(pair.Key.ToString()) == 0)
        {
            retVal += int.Parse(pair.Value.ToString());
            strRomanValue = strRomanValue.Substring(pair.Key.ToString().Length);
        }
    }
    return retVal;
}