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Locale-Sensitive Java Method


public static double parseDouble(String s)

Internationalization (I18n) Method Overview

The parseDouble method returns a double primitive value by parsing a floating point string.

I18n Issues

The problem with calling parseDouble is not locale aware. For example, if a string is set to "2,3" where a comma is used as the decimal separator, the parseDouble method will not create the correct double primitive value. This is because it is designed to assume that a period will be used as the decimal separator.

Suggested Replacement

To ensure that locale is applied when converting from double strings to double values, use the DecimalFormat class.

For example, instead of:

double myDouble = Double.parseDouble(myDecimalString);


double myDouble = 0;

//Retrieve the runtime user's locale
Locale locale = getUserLocale();

//Now call the NumberFormat factory method
//and pass the locale object
NumberFormat f = NumberFormat.getInstance(locale);

//If it is in fact an instance of DecimalFormat,
//cast it as such and use it as needed
if (f instanceof DecimalFormat) {
    try {
        myDouble = ((DecimalFormat) f).parse(myDecimalString).doubleValue();
    } catch (ParseException e) {}

Please see Number Formatting for more information.

Locale-Sensitive Java Methods


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