Start of Tutorial > Start of Trail > Start of Lesson |
Search
Feedback Form |
By invoking the methods provided by theNumberFormat
class, you can format numbers, currencies, and percentages according toLocale
. The material that follows demonstrates formatting techniques with a sample program calledNumberFormatDemo
.
You can use theNumberFormat
methods to format primitive-type numbers, such asdouble
, and their corresponding wrapper objects, such asDouble
.The following code example formats a
Double
according toLocale
. Invoking thegetNumberInstance
method returns a locale-specific instance ofNumberFormat
. Theformat
method accepts theDouble
as an argument and returns the formatted number in aString
.Double amount = new Double(345987.246); NumberFormat numberFormatter; String amountOut; numberFormatter = NumberFormat.getNumberInstance(currentLocale); amountOut = numberFormatter.format(amount); System.out.println(amountOut + " " + currentLocale.toString());The output from this example shows how the format of the same number varies with
Locale
:345 987,246 fr_FR 345.987,246 de_DE 345,987.246 en_US
If you're writing business applications, you'll probably need to format and to display currencies. You format currencies in the same manner as numbers, except that you callgetCurrencyInstance
to create a formatter. When you invoke theformat
method, it returns aString
that includes the formatted number and the appropriate currency sign.This code example shows how to format currency in a locale-specific manner:
Double currency = new Double(9876543.21); NumberFormat currencyFormatter; String currencyOut; currencyFormatter = NumberFormat.getCurrencyInstance(currentLocale); currencyOut = currencyFormatter.format(currency); System.out.println(currencyOut + " " + currentLocale.toString());The output generated by the preceding lines of code is as follows:
9 876 543,21 F fr_FR 9.876.543,21 DM de_DE $9,876,543.21 en_USAt first glance this output may look wrong to you, because the numeric values are all the same. Of course, 9 876 543,21 F is not equivalent to 9.876.543,21 DM. However, bear in mind that the
NumberFormat
class is unaware of exchange rates. The methods belonging to theNumberFormat
class format currencies but do not convert them.
You can also use the methods of theNumberFormat
class to format percentages. To get the locale-specific formatter, invoke thegetPercentInstance
method. With this formatter, a decimal fraction such as 0.75 is displayed as 75%.The following code sample shows how to format a percentage.
Double percent = new Double(0.75); NumberFormat percentFormatter; String percentOut; percentFormatter = NumberFormat.getPercentInstance(currentLocale); percentOut = percentFormatter.format(percent);
Start of Tutorial > Start of Trail > Start of Lesson |
Search
Feedback Form |
Copyright 1995-2005 Sun Microsystems, Inc. All rights reserved.