How do I convert a String to Double in Java using a specific locale?

by

Try java.text.NumberFormat. From the Javadocs:

To format a number for a different Locale, specify it in the call to getInstance.

NumberFormat nf = NumberFormat.getInstance(Locale.FRENCH);

You can also use a NumberFormat to parse numbers:

myNumber = nf.parse(myString);

parse() returns a Number; so to get a double, you must call myNumber.doubleValue():

    double myNumber = nf.parse(myString).doubleValue();

Note that parse() will never return null, so this cannot cause a NullPointerException. Instead, parse throws a checked ParseException if it fails.

Edit: I originally said that there was another way to convert to double: cast the result to Double and use unboxing. I thought that since a general-purpose instance of NumberFormat was being used (per the Javadocs for getInstance), it would always return a Double. But DJClayworth points out that the Javadocs for parse(String, ParsePosition) (which is called by parse(String)) say that a Long is returned if possible. Therefore, casting the result to Double is unsafe and should not be tried!
Thanks, DJClayworth!

More Related Contents:

  1. How can I get the current date and time in UTC or GMT in Java?
  2. How do I set the default locale in the JVM?
  3. Android: how to get the current day of the week (Monday, etc…) in the user’s language?
  4. Why does Java’s java.time.format.DateTimeFormatter#format(LocalDateTime) add a year?
  5. Java string searching ignoring accents
  6. Sort List of Strings with Localization
  7. How do I get localized date pattern string?
  8. A good date converter for Jalali Calendar in Java? [closed]
  9. en_US or en-US, which one should you use? [duplicate]
  10. Force 4-digit-year in localized strings generated from `DateTimeFormatter.ofLocalized…` in java.time
  11. What’s causing my java.net.SocketException: Connection reset? [duplicate]
  12. Get driving directions using Google Maps API v2
  13. How to convert a Java 8 Stream to an Array?
  14. Java abstract interface
  15. Get declared fields of java.lang.reflect.Fields in jdk12
  16. Wrap the string after a number of characters word-wise in Java
  17. compareTo() vs. equals()
  18. Want an eclipse java project to run ant build files automatically
  19. Implementing a mouse click event on a tile in a map
  20. Error when checking Java version: could not find java.dll
  21. Unable to get Struts2 Hello World to work using Eclipse and Maven
  22. LOG4J: Modify logged message using custom appender
  23. Why does Java permit escaped unicode characters in the source code?
  24. How to extend a final class in Java
  25. Setting socket read timeout with javax.xml.soap.SOAPConnection
  26. An enclosing instance that contains is required
  27. Creating .p12 truststore with openssl
  28. Kafka Consumer CommitFailedException
  29. Java Smooth Color Transition
  30. Java: Long result = -1: cannot convert from int to long

Leave a Comment