Java programs to add right padding to a string in such a way that total string length should be a fixed predefined number.
For example, if we have a string of length 10, and we want to increase it’s length to 15 – by adding right padding then use the example given this post.
1. How right padding is added
When you add right padding, you essentially add a character repeatedly to the end of string – until string length reaches to defined length.
For example –
howtodoinjava.com //no padding howtodoinjava.com //right padding of 4 spaces howtodoinjava.com.... //right padding of 4 dots howtodoinjava.com0000 //right padding of 4 zeros
Read More: Java remove trailing whitespaces from String
2. Java right padding with spaces
To add right padding, most useful and easy way is to use StringUtils.rightPad() method.
2.1. Maven dependency
<dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.8</version> </dependency>
2.2. Method Syntax (overloaded)
/** * @param str - the String to pad out, may be null * @param size - the size to pad to i.e. Total length of result string * @param padChar - the character or string to pad with * * @return right padded String or original String if no padding is necessary or if null String input */ public static String rightPad(final String str, final int size) {...} public static String rightPad(final String str, final int size, String padStr) {...} public static String rightPad(final String str, final int size, final char padChar) { ... }
2.3. Right padding example
//Added # character to verify padded blank spaces System.out.println( StringUtils.rightPad("howtodoinjava", 20, " ") + "#"); System.out.println( StringUtils.rightPad("howtodoinjava", 30, " ") + "#"); System.out.println( StringUtils.rightPad("howtodoinjava", 15, " ") + "#");
Program output:
howtodoinjava # howtodoinjava # howtodoinjava #
3. Java right pad a string with zeros
Java program to use StringUtils.rightPad()
method to right pad a string with zeros, by adding trailing zeros to string.
System.out.println( StringUtils.rightPad("0123456789", 10, "0") ); System.out.println( StringUtils.rightPad("0123", 10, "0") ); System.out.println( StringUtils.rightPad("012345", 10, "0") );
Program output:
0123456789 0123000000 0123450000
4. Summary
In above examples, we learned to right pad string with spaces to fixed length. We also saw to right pad a number with zeros.
Use this right padding to format strings to fixed length – to display in UI.
Happy Learning !!
Reference:
Dharmedra
which package should be imported for using this?