How to set decimals to only 2 digits in Doubles?

[James Dekker]

Hello,

I am have the following method (pseudo code) which sums up totals:

public String getSum() {
     // For Loop {
         Double totalDollarAmount = 0.0;
         Double amount = transactionTotalAmount.doubleValue();
         totalDollarAmount = totalDollarAmount + amount;
     }	 // For Loop ending
     return totalDollarAmount.toString();
}

Sometimes, my method returns values such as this:

25.00
125.00024
131.35001
33.0

How to I set up it so it only shows two digits, as follows:

25.00
125.00
131.35
33.00

Thank you for taking the time to read this...

[Jesper de Jong]

First of all, is there a reason why you use Double objects instead of the primitive type double? Also note that floating-point data types are not suitable for storing amounts of money in real-world programs because floating-point numbers have limited precision, you can get roundoff errors which are not acceptable when dealing with money.

There are several ways to print numbers with nice formatting. One way is to use System.out.printf(). For example:

double number = 123.675;
System.out.printf("%.2f", number);

If you don't want to print it, but just return the result formatted in a string, use String.format("%.2f", number); instead (that returns a String).

Another, slightly more cumbersome way, is to use class java.text.NumberFormat.

[James Dekker]

Thanks Jesper,

In my situation I was going to display in inside a JSP...

I ended up using the DecimalFormat class:

NumberFormat formatter = new DecimalFormat("#0.00");
formatter.format(value);

Thanks for the response!

[Rob Spoor]

You can use the static String.format method to create a String with the same type of arguments to System.out.printf:

double number = 123.675;   
String s = String.format(("%.2f", number);