将英尺和英寸转换为厘米和反之亦然的奇怪问题

public static double convertFeetandInchesToCentimeter(String feet, String inches) {
    double heightInFeet = 0;
    double heightInInches = 0;
    try {
        if (feet != null && feet.trim().length() != 0) {
            heightInFeet = Double.parseDouble(feet);
        }
        if (inches != null && inches.trim().length() != 0) {
            heightInInches = Double.parseDouble(inches);
        }
    } catch (NumberFormatException nfe) {

    }
    return (heightInFeet * 30.48) + (heightInInches * 2.54);
}
public static double convertFeetandInchesToCent