Java Output Formatting

At times we want the output of a program to be printed in a given specific format. In the C programming language this is possible using the printf( ) function. In this section, we will discuss the different output formatting.

Let's discuss how we can format the output in Java.

There are two methods that can be used to format the output in Java:

Using the printf( ) Method
Using the format( ) Method

Formatting output using System.out.printf( ) Method

The implementation of this method is very easy as it is similar to the printf( ) function in C programming.

FormattedOutput1.java

public class FormattedOutput1
{
  public static void main( String args[ ] )
  {
    // printing the string value on the console
    String str = " JavaTpoint " ;
    System.out.printf( " \n Printing the String value : %s \n ", str ) ;
    // printing the integer value on the console
    int x = 512 ;
    System.out.printf( " \n Printing the integer value : x = %d \n ", x ) ;
    // printing the decimal value on the console
    float f = 5.25412368f ;
    System.out.printf( " \n Printing the decimal value : %f \n ", f ) ;
    // this formatting is used to specify the width un to which the digits can extend
    System.out.printf( " \n Formatting the output to specific width : n = %.4f \n ", f ) ;
    // this formatting will print it up to 2 decimal places
    System.out.printf( " \n Formatted the output with precision : PI = %.2f \n ", f ) ;
    // here number is formatted from right margin and occupies a width of 20 characters
    System.out.printf( " \n Formatted to right margin : n = %20.4f \n ", f ) ;
  }
}

Output:

Printing the String value :  JavaTpoint  
 Printing the integer value : x = 512 
 Printing the decimal value : 5.254124 
 Formatting the output to specific width : n = 5.2541 
 Formatted the output with precision : PI = 5.25 
 Formatted to right margin : n = 5.2541

System.out.format( ) is equivalent to printf( ) and can also be used.

An important point to note is that System.out.print( ) and System.out.println( ) take a single argument, but the printf( ) method can accept multiple arguments.

Formatting Using the DecimalFormat Class:

DecimalFormat is used to format decimal numbers.

FormattedOutput2.java

import java.text.DecimalFormat ;
// definition of the class 
public class FormattedOutput2
{
  public static void main( String args[ ] )
  {
    double x = 123.4567 ;
    // printing the number
    System.out.printf( " \n The number is : %f \n ", x ) ;    
    // printing only the numeric part of the floating number
    DecimalFormat ft = new DecimalFormat( " #### " ) ;
    System.out.println( " \n Without fraction part the number is : " + ft.format( x ) ) ;
    // printing the number only upto 2 decimal places
    ft = new DecimalFormat( " #.## " ) ;
    System.out.println( " \n Formatted number with the specified precision is = " + ft.format( x ) ) ;
    // automatically appends zero to the rightmost part of decimal, instead of #, we use digit 0
    ft = new DecimalFormat( " #.000000 " ) ;
    System.out.println( " \n Appending the zeroes to the right of the number = " + ft.format( x ) ) ;
    // automatically appends zero to the leftmost of decimal number instead of #, we use digit 0
    ft = new DecimalFormat( " 00000.00 " ) ;
    System.out.println( " \n Appending the zeroes to the left of the number = "+ ft.format( x ) ) ;
    // formatting money in dollars
    double income = 550000.789 ;
    ft = new DecimalFormat( " $###,###.## "  ) ;
    System.out.println( " \n Your Formatted Income in Dollars : " + ft.format( income ) ) ;
  }
}

Output:

 The number is : 123.456700 
 Without fraction part the number is :  123 
 Formatted number with the specified precision is =  123.46 
 Appending the zeroes to the right of the number =  123.456700 
 Appending the zeroes to the left of the number =  00123.46 
 Your Formatted Income in Dollars :  $550,000.79

Java String Format Specifiers

Here, we are providing a table of format specifiers supported by the Java String.

Format Specifier	Data Type	Output
%a	floating point ( except BigDecima l)	Returns Hex output of floating-point number.
%b	Any type	" true " if non-null, " false " if null
%c	Character	Unicode character
%d	integer ( incl. byte, short, int, long, bigint )	Decimal Integer
%e	floating point	Decimal number in scientific notation
%f	floating point	Decimal number
%g	floating point	Decimal number, possibly in scientific notation depending on the precision and value.
%h	any type	Hex String of value from hashCode( ) method.
%n	None	Platform-specific line separator.
%o	integer ( incl. byte, short, int, long, bigint )	Octal number
%s	any type	String value
%t	Date/Time ( incl. long, Calendar, Date and TemporalAccessor )	%t is the prefix for Date/Time conversions. More formatting flags are needed after this. See Date/Time conversion below.
%x	integer ( incl. byte, short, int, long, bigint )	Hex string.