Double decimal formatting in Java

Question

One of the way would be using NumberFormat.

NumberFormat formatter = new DecimalFormat("#0.00");     
System.out.println(formatter.format(4.0));

Output:

4.00

With Java 8, you can use format method..: -

System.out.format("%.2f", 4.0); // OR

System.out.printf("%.2f", 4.0); 

• f is used for floating point value..
• 2 after decimal denotes, number of decimal places after .

For most Java versions, you can use DecimalFormat: -

    DecimalFormat formatter = new DecimalFormat("#0.00");
    double d = 4.0;
    System.out.println(formatter.format(d));

Use String.format:

String.format("%.2f", 4.52135);

As per docs:

The locale always used is the one returned by Locale.getDefault().

Using String.format, you can do this:

double price = 52000;
String.format("$%,.2f", price);

Notice the comma which makes this different from @Vincent's answer

Output:

$52,000.00

A good resource for formatting is the official java page on the subject

You could always use the static method printf from System.out - you'd then implement the corresponding formatter; this saves heap space in which other examples required you to do.

Ex:

System.out.format("%.4f %n", 4.0); 

System.out.printf("%.2f %n", 4.0); 

Saves heap space which is a pretty big bonus, nonetheless I hold the opinion that this example is much more manageable than any other answer, especially since most programmers know the printf function from C (Java changes the function/method slightly though).

double d = 4.0;
DecimalFormat nf = DecimalFormat.getInstance(Locale.ENGLISH);
System.out.println(nf.format("#.##"));