Java：货币到区域设置映射可能吗？

I have a value stored in a DB correlating to a monetary amount, say 10.0. I also have access to the Currency/CurrencyCode. How can I use NumberFormat/DecimalFormat/(other?) to format when I don't know the Locale? According to the docs it will pick a default locale which won't work with a foreign Currency.

我有一个存储在数据库中的值与货币金额相关,比如10.0。我也可以访问Currency / CurrencyCode。当我不知道Locale时,如何使用NumberFormat / DecimalFormat /(other?)格式化?根据文档,它将选择一个不适用于外币的默认语言环境。

5 个解决方案

#1

The correct behavior, generally speaking, is to format the amount in the User's preferred locale, not the currency's typical locale. On the client side, you'll have the user's preference (Locale.getDefault()); if you are doing something on the web server side, use the Accept-Language or, preferably, the page content's locale to obtain the proper a locale.

一般来说,正确的行为是格式化用户首选区域设置中的金额,而不是货币的典型区域设置。在客户端,您将拥有用户的首选项(Locale.getDefault());如果您在Web服务器端执行某些操作,请使用Accept-Language或最好是页面内容的区域设置来获取正确的区域设置。

The reasoning is this: An English-US user will understand € 10,000,000.15 but not the suitable-for-Germany equivalent, € 10.000.000,15

理由是这样的:英美用户将理解10,000,000欧元.15但不是适合德国的等价物,€10.000.000,15

The currency itself doesn't contain enough information to infer a suitable locale, anyway.

无论如何,货币本身不包含足以推断合适区域的信息。

#2

JasonTrue is correct, but you can override the currency of the NumberFormat's locale:

JasonTrue是正确的,但您可以覆盖NumberFormat的语言环境的货币:

NumberFormat numberFormat = NumberFormat.getCurrencyInstance(locale);
//the user may have selected a different currency than the default for their locale
Currency currency = Currency.getInstance("GBP");
numberFormat.setCurrency(currency);
numberFormat.format(amount);

#3

What if the currency code is EUR? And, while it has taken a beating, USD is still used throughout the world. Inferring the locale from the currency code seems unreliable. Can you introduce an explicit user preference for the locale instead?

如果货币代码是欧元怎么办?而且,虽然它遭受了打击,但美元仍然在全世界使用。从货币代码中推断出区域设置似乎不可靠。您是否可以为区域设置引入明确的用户首选项?

The information you are looking for is not part of the built-in Java currency database, so there is not an API for it. You could create your own table for the many cases that are unambiguous.

您要查找的信息不是内置Java货币数据库的一部分,因此没有API。您可以为许多明确的案例创建自己的表。

#4

I would say that if your database is storing a currency value it should be hanging onto the units at the same time. It sounds like you're doing that now. Can you add the Locale to the database at the same time? Could be a decent solution.

我会说,如果你的数据库存储货币值,它应该同时挂在单位上。听起来你现在正在这样做。您可以同时将Locale添加到数据库吗?可能是一个体面的解决方案

#5

Here's a way to determine the locale from the currency code

这是一种根据货币代码确定区域设置的方法

let locale = NSLocale(localeIdentifier: NSLocale.canonicalLocaleIdentifierFromString(NSLocale.localeIdentifierFromComponents([NSLocaleCurrencyCode: currencyCode])))

let formatter = NSNumberFormatter()
formatter.numberStyle = .CurrencyStyle
formatter.currencyCode = currencyCode
formatter.locale = locale
formatter.maximumFractionDigits = 2
formatter.stringFromNumber(number)

#1