Java：用逗号格式化数字

Question

I just want the numbers to be output in "well readable" format. eg you can output 100000 as 100.000 which would be more readable.

Is there an already existing method that can be used for this?

Answer 1

You can use NumberFormat :

int n = 100000;
String formatted = NumberFormat.getInstance().format(n);
System.out.println(formatted);

Output:

100,000

Answer 2

You can use DecimalFormat ( Java 7+ ):

var dfs = new DecimalFormatSymbols();
dfs.setGroupingSeparator('.');
var df = new DecimalFormat("###,##0", dfs);
System.out.println(df.format(100000));

output:

100.000

DecimalFormat has more flexibility to convert numbers to string by pattern.