Formatting Currencies in Foreign Locales in Java

问题

I'm doing my best to find a way to format foreign currencies across various locales which are not default for that currency, using Java. I've found java.util.Currency, which can represent the proper symbol to use for various locales. That is, for USD, it provides me the symbol $ in the US, and US$ or USD in other nations. Also, I've found java.text.NumberFormat, which will format a currency for a specific locale. My problem - util.Currency will provide proper symbols and codes for representing currencies in their non-default locales, but will not format currency in any locale-specific way. NumberFormat assumes that the number I pass it, with a locale, is the currency of that locale, not a foreign currency.

For example, if I use getCurrencyInstance(Locale.GERMANY) and then format (1000) it assumes I am formatting 1000 euro. In reality, I may need the correct German-localized representation (correct decimal and thousands separator, whether to put the symbol before or after the amount) for USD, or Yen, or any other currency. The best I've been able to derive so far is to format a number using NumberFormat, then search the output for non-digit characters and replace them with symbols derived from util.Currency. However, this is very brittle, and probably not reliable enough for my purposes. Ideas? Any help is much appreciated.

回答1:

Try using setCurrency on the instance returned by getCurrencyInstance(Locale.GERMANY)

Broken:

java.text.NumberFormat format = java.text.NumberFormat.getCurrencyInstance(java.util.Locale.GERMANY);
System.out.println(format.format(23));

Output: 23,00 €

Fixed:

java.util.Currency usd = java.util.Currency.getInstance("USD");
java.text.NumberFormat format = java.text.NumberFormat.getCurrencyInstance(java.util.Locale.GERMANY);
format.setCurrency(usd);
System.out.println(format.format(23));

Output: 23,00 USD

回答2:

I would add to answer from les2 https://stackoverflow.com/a/7828512/1536382 that I believe the number of fraction digits is not taken from the currency, it must be set manually, otherwise if client (NumberFormat) has JAPAN locale and Currency is EURO or en_US, then the amount is displayed 'a la' Yen', without fraction digits, but this is not as expected since in euro decimals are relevant, also for Japanese ;-).

So les2 example could be improved adding format.setMaximumFractionDigits(usd.getDefaultFractionDigits());, that in that particular case of the example is not relevant but it becomes relevant using a number with decimals and Locale.JAPAN as locale for NumberFormat.

    java.util.Currency usd = java.util.Currency.getInstance("USD");
    java.text.NumberFormat format = java.text.NumberFormat.getCurrencyInstance(
          java.util.Locale.JAPAN);
    format.setCurrency(usd);
    System.out.println(format.format(23.23));
    format.setMaximumFractionDigits(usd.getDefaultFractionDigits());
    System.out.println(format.format(23.23));

will output:

USD23
USD23.23

In NumberFormat code something similar is done for the initial/default currency of the format, calling method DecimalFormat#adjustForCurrencyDefaultFractionDigits. This operation is not done when the currency is changed afterwards with NumberFormat.setCurrency

回答3:

import java.util.*;
import java.text.*;

public class Solution {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        double payment = scanner.nextDouble();
        scanner.close();

        NumberFormat lp;  //Local Payment

        lp = NumberFormat.getCurrencyInstance(Locale.US);
        System.out.println("US: " + lp.format(payment));

        lp = NumberFormat.getCurrencyInstance(new Locale("en", "in"));
        System.out.println("India: " + lp.format(payment));

        lp = NumberFormat.getCurrencyInstance(Locale.CHINA);
        System.out.println("China: " + lp.format(payment));

        lp = NumberFormat.getCurrencyInstance(Locale.FRANCE);
        System.out.println("France: " + lp.format(payment));
    }
}

回答4:

Scanner scanner = new Scanner(System.in);
double payment = scanner.nextDouble();
scanner.close();
java.text.NumberFormat formatUS = java.text.NumberFormat.getCurrencyInstance(java.util.Locale.US);
String us=formatUS.format(payment);
java.text.NumberFormat formatIn = java.text.NumberFormat.getCurrencyInstance(new java.util.Locale("en","in"));
String india=formatIn.format(payment);
java.text.NumberFormat formatChina = java.text.NumberFormat.getCurrencyInstance(java.util.Locale.CHINA);
String china=formatChina.format(payment);
java.text.NumberFormat formatFrance = java.text.NumberFormat.getCurrencyInstance(java.util.Locale.FRANCE);
String france=formatFrance.format(payment);

System.out.println("US: " + us);
System.out.println("India: " + india);
System.out.println("China: " + china);
System.out.println("France: " + france);

回答5:

Better way is just to import java.util.Locale

Then use the method like this:

NumberFormat.getCurrencyInstance(Locale.theCountryYouWant);

e.g. NumberFormat.getCurrencyInstance(Locale.US);

回答6:

Code below, Ref Java Locale:

Scanner scanner = new Scanner(System.in);
double payment = scanner.nextDouble();
scanner.close();

// Write your code here.
String china = NumberFormat.getCurrencyInstance(new Locale("zh", "CN")).format(payment);
String india = NumberFormat.getCurrencyInstance(new Locale("en", "IN")).format(payment);
String us = NumberFormat.getCurrencyInstance(Locale.US).format(payment);
String france = NumberFormat.getCurrencyInstance(Locale.FRANCE).format(payment);

System.out.println("US: " + us);
System.out.println("India: " + india);
System.out.println("China: " + china);
System.out.println("France: " + france);

来源：https://stackoverflow.com/questions/7828364/formatting-currencies-in-foreign-locales-in-java

标签

java

format

currency