如何在java中格式化int数字？

Question

I am trying to apply this format to a given int number #´###,### I tried with DecimalFormat class but it only allows to have one grouping separator symbol when I need to have two the accute accent for millions and commas for thousands.

So at the end I can format values like 1,000 or millions in this way 1´000,000

Answer 1

I always prefer to use String.format, but I am not sure if there is a Locale that would format numbers like that either. Here is some code that will do the job though.

// Not sure if you wanted to start with a number or a string. Adjust accordingly
String stringValue = "1000000";
float floatValue = Float.valueOf(stringValue);

// Format the string to a known format
String formattedValue = String.format(Locale.US, "%,.2f", floatValue);

// Split the string on the separator
String[] parts = formattedValue.split(",");

// Put the parts back together with the special separators
String specialFormattedString = "";
int partsRemaining = parts.length;
for(int i=0;i<parts.length;i++)
{
    specialFormattedString += parts[i];
    partsRemaining--;
    if(partsRemaining > 1)
        specialFormattedString += "`";
    else if(partsRemaining == 1)
        specialFormattedString += ",";
}

Answer 2

Try this, these Locale formats in your required format.

    List<Locale> locales = Arrays.asList(new Locale("it", "CH"), new Locale("fr", "CH"), new Locale("de", "CH"));
    for (Locale locale : locales) {
        DecimalFormat df = (DecimalFormat) NumberFormat.getCurrencyInstance(locale);
        DecimalFormatSymbols dfs = df.getDecimalFormatSymbols();
        dfs.setCurrencySymbol("");
        df.setDecimalFormatSymbols(dfs);
        System.out.println(String.format("%5s %15s %15s", locale, format(df.format(1000)), format(df.format(1_000_000))));
    }

util method

private static String format(String str) {
    int index = str.lastIndexOf('\'');
    if (index > 0) {
        return new StringBuilder(str).replace(index, index + 1, ",").toString();
    }
    return str;
}

output

it_CH        1,000.00    1'000,000.00
fr_CH        1,000.00    1'000,000.00
de_CH        1,000.00    1'000,000.00

set df.setMaximumFractionDigits(0); to remove the fractions

output

it_CH           1,000       1'000,000
fr_CH           1,000       1'000,000
de_CH           1,000       1'000,000

Answer 3

I found useful the link @Roshan provide in comments, this solution is using regex expression and replaceFirst method

public static String audienceFormat(int number) {
    String value = String.valueOf(number);

    if (value.length() > 6) {
            value = value.replaceFirst("(\\d{1,3})(\\d{3})(\\d{3})", "$1\u00B4$2,$3");
        } else if (value.length() >=5 && value.length() <= 6) {
            value = value.replaceFirst("(\\d{2,3})(\\d{3})", "$1,$2");
        }  else {
            value = value.replaceFirst("(\\d{1})(\\d+)", "$1,$2");
        }

    return value;
} 

I don't know if this solution has a performance impact, also I am rockie with regex, so this code might be shorted.

Answer 4

Maybe try using this, the "#" in place with the units you want before the space or comma.

String num = "1000500000.574";
    String newnew = new   DecimalFormat("#,###.##").format(Double.parseDouble(number));