Locale-Sensitive Java Constructor

java.lang.Float

Float(double value)
Float(float value)
Float(String s)

Internationalization (I18n) Method Overview

The Float class wraps a float primitive type in an object. To construct a Float object, you pass in either a double value, a float value, or a floating point string.

I18n Issues

The problem with calling the Float constructor with a string parameter is that it is not locale aware. For example, if a string is set to "2,3" where a comma is used as the decimal separator, the Float constructor will not create the correct Float object. 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 between float values and float strings, use the DecimalFormat class.

For example, instead of:

Float myFloat = new Float(myFloatString);


Use:

Float myFloat = null;

//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 {
        myFloat = new Float(((DecimalFormat) f).parse(myFloatString).floatValue());
    } catch (ParseException e) {}
}


Please see Number Formatting for more information.