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javastringdouble

Parse String to Double with null values

I have to convert Strings to Doubles, but may be I have a null value. Does it work with Double.parseDouble(stringValue) or Double.valueOf(stringValue)?

What is the difference between this two methods?

Thank you in advance.

Solution

  • Neither method makes any difference. Both will throw a NullPointerExecption. Instead, you need to add a helper method which returns a Double e.g.

    static Double parseDouble(String s) {
    return s == null ? null : Double.parseDouble(s);
}

    or you can return a double by having a default value

    static double parseDouble(String s, double otherwise) {
    return s == null ? otherwise : Double.parseDouble(s);
}

    a suitable value might be Double.NaN

    static double parseDouble(String s) {
    return s == null ? Double.NaN : Double.parseDouble(s);
}