How to format Double with dot?

问题:

How do I format a Double with String.format to String with a dot between the integer and decimal part?

String s = String.format("%.2f", price);

The above formats only with a comma: ",".

回答1:

String.format(String, Object ...) is using your JVM's default locale. You can use whatever locale using String.format(Locale, String, Object ...) or java.util.Formatter directly.

String s = String.format(Locale.US, "%.2f", price);

or

String s = new Formatter(Locale.US).format("%.2f", price);

or

// do this at application startup, e.g. in your main() method
Locale.setDefault(Locale.US);

// now you can use String.format(..) as you did before
String s = String.format("%.2f", price);

or

// set locale using system properties at JVM startup
java -Duser.language=en -Duser.region=US ...

回答2:

Based on this post you can do it like this and it works for me on Android 7.0

import java.text.DecimalFormat
import java.text.DecimalFormatSymbols

DecimalFormat df = new DecimalFormat("#,##0.00");
df.setDecimalFormatSymbols(new DecimalFormatSymbols(Locale.ITALY));
System.out.println(df.format(yourNumber)); //will output 123.456,78

This way you have dot and comma based on your Locale

Answer edited and fixed thanks to Kevin van Mierlo comment

回答3:

If it works the same as in PHP and C#, you might need to set your locale somehow. Might find something more about that in the Java Internationalization FAQ.