Replace grouping separator of DecimalFormat in for

问题:

I've used DecimalFormat df = new DecimalFormat("#,###.00"); to format a BigDecimal.

Now, I want to use that formatted value (say it is '1 250,00') to create new BigDecimal. I've tried this:

BigDecimal result = new BigDecimal(model.getValue().replace(",",".").replace(" ",""));

But that space between 1 and 2 in 1 250.00 is not replaced. How can I fix it?

Example:

DecimalFormat df = new DecimalFormat("#,###.00");
BigDecimal example = new BigDecimal("1250");
String str = df.format(example);
System.out.println(str.replace(",",".").replace(" ",""));

回答1:

DecimalFormat Javadoc specifies that the symbol , is the grouping separator. By default, for your locale, this separator is not a space but a non-breaking space. This can be shown by the following code:

DecimalFormatSymbols symbols = new DecimalFormatSymbols(Locale.forLanguageTag("ru-RU"));
System.out.println((int) symbols.getGroupingSeparator());

You will see that the int printed is 160, which corresponds to "Non-breaking space" in ISO-8859-1.

To remove that character, we can use its Unicode representation and replace that:

DecimalFormat df = new DecimalFormat("#,###.00");
String str = df.format(new BigDecimal("1250"));
System.out.println(str.replace(",", ".").replace("\u00A0", ""));

For a more general solution, not depending on the current locale, we could retrieve the grouping separator and use that directly:

DecimalFormat df = new DecimalFormat("#,###.00");
String groupingSeparator = String.valueOf(df.getDecimalFormatSymbols().getGroupingSeparator());
String str = df.format(new BigDecimal("1250"));
System.out.println(str.replace(",", ".").replace(groupingSeparator, ""));

回答2:

You can set grouping separator (e.g. thousand separator) character in your pattern by using DecimalFormatSymbols. It looks that in your locale it is non-breaking space so try to set it to normal space like

DecimalFormatSymbols symbols = new DecimalFormatSymbols(Locale.getDefault());
symbols.setGroupingSeparator(' ');//simple space

DecimalFormat df = new DecimalFormat("#,###.00", symbols);

BigDecimal example = new BigDecimal("1250");
String str = df.format(example);

Now your formatter will use simple space so you will be able to replace it with your code

System.out.println(str.replace(",", ".").replaceAll(" ", ""));

Output: 1250.00.

回答3:

You can use the parse method from your DecimalFormat object.

df.setParseBigDecimal(true);    
BigDecimal bigDecimal = (BigDecimal) df.parse(model.getValue());

Take a look at the selected answer in this SO question.

回答4:

In your format

new DecimalFormat("#,###.00"); 

the symbol , is meant for grouping separator. After removing the symbol , from your format you get the output 1250.00 (without grouping separator in your case space).

DecimalFormat df = new DecimalFormat("####.00");
BigDecimal example = new BigDecimal("1250");
String str = df.format(example);
System.out.println(str.replace(",",".").replace(" ",""));

Output: 1250.00

There is alternative (2nd) solution and it works without altering your format "#,###.00". Use .setGroupingSize(0) from DecimalFormat:

DecimalFormat df = new DecimalFormat("#,###.00");
df.setGroupingSize(0);
BigDecimal example = new BigDecimal("1250");
String str = df.format(example);
System.out.println(str);

Output: 1250.00