DecimalFormat depending on system settings? - java

I'm having the strangest thing with a DecimalFormat.
I'm using it in an webapplication.
I setup some test and it keeps on failing with me locally.
A friend of me ran it and he was able to successfully ran the JUnit tests.
The strange part is that on our server the application runs it perfectly without any problems either.
Could it be that Java depends on the system settings like valuta and number settings?
Or could there be another reason?
This is how my piece of code looks like:
public String generateFormatPrice(double price) throws Exception {
DecimalFormat format1 = new DecimalFormat("#,##0.00");
String tmp = format1.format(price).replace(".", "&");
String[] tmps = tmp.split("&");
return tmps[0].replace(',', '.') + "," + tmps[1];
}
Thanks a lot in advance!

This code is indeed locale-specific. If your code depends on being in a locale such as the USA where "." is the decimal separator and "," is the thousands separator, and then you run this code on a server set to, for example, the German locale, it will fail.
Consider using this constructor, which allows you to explicitly specify which symbols you are using.
EDIT: as far as I can tell you are trying to format numbers using "." as the thousands separator and "," as the decimal separator. In other words, the format used in France and Germany. Here's one approach that will achieve this:
public static String generateFormatPrice(double price) {
final NumberFormat format = NumberFormat.getNumberInstance(Locale.GERMANY);
format.setMinimumFractionDigits(2);
format.setMaximumFractionDigits(2);
return format.format(price);
}
Also, you shouldn't be using a double to hold a monetary value - you are going to encounter some nasty bugs if you do that.

Related

Why does the NumberFormat returns blank fields?

So a few days ago I encountered a weird problem however, I didn't change any that kind of code. The problem is the format I'm getting from my method which I used for years. All commas are now spaces (blank fields) and I have no idea what is causing this.
public static String toFancyCost(int num) {
return NumberFormat.getInstance().format((Integer) num);
}
Before even this happened the String I received was looking like for example 2,181,273 and not like 2 181 273.
You must have changed your system locale by accident. The implementation of NumberFormat.getInstance() (on 1.8.0_131):
public final static NumberFormat getInstance() {
return getInstance(Locale.getDefault(Locale.Category.FORMAT), NUMBERSTYLE);
}
It uses formatting specified by the default locale. and the java docs on Locale.getDefault say:
The Java Virtual Machine sets the default locale during startup based
on the host environment. It is used by many locale-sensitive methods
if no locale is explicitly specified. It can be changed using the
setDefault method.
If you were to use NumberFormat.getInstance(Locale) you can specify which locale the NumberFormat should use.
Your systems default local is using a space as thousands separator, number format retured by getInstance() uses settings from system's default local.
As commented above, somehow the system default may have been modified. Let's stick the code to set the locale when formatting by using below to avoid any issues.
int number = 345678987;
NumberFormat numberFormat = NumberFormat.getNumberInstance(Locale.US);// Locale.US or any other locale you required
String numberAsString = numberFormat.format(number);
System.out.println(numberAsString);
response:
345,678,987
when I use the below for example with Locale.CANADA_FRENCH
int number = 345678987;
NumberFormat numberFormat = NumberFormat.getNumberInstance(Locale.CANADA_FRENCH);
String numberAsString = numberFormat.format(number);
System.out.println(numberAsString);
response:
345 678 987
So in your case also locale may have been causing issues, so please explictly set locale.

Date-format Behaving Peculiarly

we have a legacy system where they would be generating the current date and then sets that as a header to an excel.
Below java code in the simplified piece of my logic
Sometimes for this program I get the header output in a peculiar form
As example scenario is my code is supposed to produce an header of 14 characters like 20170529121599 but sometimes it is producing a header of 15 characters like 201705291215992
Expected : 20170529121599
Output : 201705291215992
Why am I getting that extra character in some rare cases ?
This happens very rarely only and when this happens this extra character is causing the downstream system to fail.
Fix : We can fix this by timing the extra charters but I really want to know the reason behind this so that it would help to fix similar issues.
Can someone help me with this ?
import java.text.DateFormatSymbols;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
public class TestDateGeneration {
public static void main(String args[]) {
DateFormatSymbols symbols;
SimpleDateFormat formatter;
symbols = new DateFormatSymbols(new Locale("en", "US"));
formatter = new SimpleDateFormat("E", symbols);
java.util.Date todayDate = new java.util.Date();
String header = "";
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmmss");
String formatedDate = dateFormat.format(todayDate);
header = formatedDate+"\t";
System.out.println("output header " +header);
}
}
Besides being incredibly difficult to read, your code doesn't produce your output (hint: include "formatedDate" in your println() call). An actual failing test would probably result in a better answer.
So if I were to guess at why it's not doing what you want, I would guess that your format is actually "yyyyMMddHHmmSS". The capital S means milliseconds (which is consistent with what your reported output shows). Note that "99" is invalid for seconds in the minute, but "990" and "992" are both valid milliseconds.

Java DecimalFormat - incorrect number format in linux

I have a problem with parsing decimal number in Linux environment. When I parse in Windows, everything's all right.
Below, code snippet
String price;
DecimalFormat FORMATTER = (DecimalFormat)DecimalFormat.getInstance();
double customPrice = FORMATTER.parse(price).doubleValue();
And results
When price='9' Then customPrice='9.0' - it is ok
When price='1,00' Then customPrice='100.0' - it is wrong
When price='25,00' Then customPrice='2500.0' - it is wrong
Can you tell me what the problem is ?
Thanks
Read here here about locales, probably you're using en_US which causes the ',' symbol to separate groups of thousands.
you can use also
DecimalFormatSymbols unusualSymbols = new DecimalFormatSymbols(currentLocale);
unusualSymbols.setDecimalSeparator(',');
DecimalFormat weirdFormatter = new DecimalFormat(strange, unusualSymbols);
weirdFormatter.setGroupingSize(4);
to state your own sepeartors
You can change the decimal separator of DecimalFormat. The easiest way by using a NumberFormat with the desired locale, e.g.:
NumberFormat FORMATTER = NumberFormat.getNumberInstance(Locale.GERMAN);
double customPrice = FORMATTER.parse(price).doubleValue();

Java NumberFormatException Legacy Code

I have a legacy program (java 1.4) running under Tomcat/Jboss, however, i have copy it to a new server (java 1.7) and it throws the following exception.
java.lang.NumberFormatException: For input string: "0000000000000000009011,00"
sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1250)
java.lang.Double.valueOf(Double.java:504)
java.lang.Double.<init>(Double.java:597)
Since i don't have access to the source, is there any way to fix this? i haven't try with java 1.4 for the moment
You schould look to jvm parameters on old server. Your language parameters will change comma to dot actually so you do not need any code changes.
I think its not due to java version. Replace comma(,) with "" or period(.)
For example conside a string : String str = "0000000000000000009011,00";
Now you can try -
double result = Double.valueOf(str.replace(",", "."));
or
double result = Double.valueOf(str.replace(",", ""));
Rather use NumberFormat for parsing:
NumberFormat format = NumberFormat.getInstance(Locale.FRANCE);
Number number = format.parse("0000000000000000009011,00");
double d = number.doubleValue();
This way you can select the right locale for the number representation. In the example above I used France - they use a comma for the decimal point.

How to format Double with dot?

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: ",".
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 ...
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
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.

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