检查分组分隔符是否为空格

Question

I am trying to check wether a grouping separator ( char ) is a space or not. It's the case for the french locale but my test always prints false .

DecimalFormat formatter = (DecimalFormat) DecimalFormat.getInstance(Locale.forLanguageTag("fr"));
char ch = formatter.getDecimalFormatSymbols().getGroupingSeparator();
System.out.println(ch == ' '); // false
System.out.println(Character.isWhitespace(ch)); // false

Answer 1

The unicode symbol you receive is not a normal whitespace . It's a no-break space . Your char has the integer representation of 160 not 32 . To check that you should use:

Character.isSpaceChar(ch);

That method checks if a character is a space according to the unicode standard.

The following method checks if a charactre is a space according to Java specification.

Character.isWhitespace(ch);

A detailed description of the criteria can be found at the documentations.

Answer 2

The grouping character is not space, but 160. This will output true and true

    DecimalFormat formatter = (DecimalFormat) DecimalFormat.getInstance(Locale.forLanguageTag("fr"));
    char ch = formatter.getDecimalFormatSymbols().getGroupingSeparator();
    System.out.println(ch == 160); 
    System.out.println(Character.isSpaceChar(ch));

Answer 3

It's non-breaking space

getGroupingSeparator() return non-breaking-space. so you can check it with specific unicode of non-breaking-space.

 public static void main(String[] args) {
    DecimalFormat formatter = (DecimalFormat) DecimalFormat.getInstance(Locale.forLanguageTag("fr"));
    char ch = formatter.getDecimalFormatSymbols().getGroupingSeparator();
    System.out.println(formatter.getDecimalFormatSymbols().getGroupingSeparator() == '\u00A0'); // true
    System.out.println(ch == ' '); // false
    System.out.println(Character.isWhitespace(ch)); // false
}