Java Reference
In-Depth Information
finally {
if (fm != null) {
fm.close();
}
}
The
format()
method of the
Formatter
class is overloaded. Its declarations are as follows.
•
Formatter format(String format, Object... args)
Formatter format(Locale l, String format, Object... args)
The first version of the
format()
method uses the default locale for formatting. The second version allows
you to specify a locale. The
format()
/
printf()
method of the
PrintStream
class and the
format()
method of the
String
class provide the same two versions of the
format()
method, which accept the same types of arguments.
This discussion of the
format()
method of the
Formatter
class equally applies to these convenience methods in the
PrintStream
and
String
classes.
The
Formatter
class uses the locale-specific formatting whenever it is applicable. For example, if you want to
format a decimal number, say 12.89, the number is formatted as 12,89 (notice a comma between 12 and 89) in
France whereas it is formatted as 12.89 (notice a dot between 12 and 89) in the United States. The locale argument of
the
format()
method is used to format text in a locale-specific format. The following snippet of code demonstrates
the effects of locale-specific formatting. Note the difference in the formatted output for US and France for the same
input values.
•
System.out.printf(Locale.US, "In US: %1$.2f %n", 12.89);
System.out.printf(Locale.FRANCE, "In France: %1$.2f %n", 12.89);
Date dt = new Date();
System.out.printf(Locale.US, "In US: %tA %n", dt);
System.out.printf(Locale.FRANCE, "In France: %tA %n", dt);
In US: 12.89
In France: 12,89
In US: Friday
In France: vendredi
The Details
Formatting data using a
Formatter
requires two types of inputs:
•
A format string
•
A list of values
The format string is the template that defines how the output will look. It contains zero or more occurrences of
fixed texts and zero or more embedded format specifiers. No formatting is applied to the fixed text.
A format specifier serves two purposes. It acts as a placeholder for the formatted data inside the format string and
it specifies how the data should be formatted.
Let's consider the following example. Suppose you want to print a text with the birth date of a person. The
following is an example of such a text:
January 16, 1970 is John's birth day.
