Adding whitespace in Java

Question

There is a class trim() to remove white spaces, how about adding/padding?

Note: " " is not the solution.

Solution 1

I think you are talking about padding strings with spaces.

One way to do this is with string format codes.

For example, if you want to pad a string to a certain length with spaces, use something like this:

String padded = String.format("%-20s", str);

In a formatter, % introduces a format sequence. The - means that the string will be left-justified (spaces will be added at the end of the string). The 20 means the resulting string will be 20 characters long. The s is the character string format code, and ends the format sequence.

Solution 2

Use the StringUtils class, it also includes null check

StringUtils.leftPad(String str, int size)
StringUtils.rightPad(String str, int size)

Solution 3

There's a few approaches for this:

1. Create a char array then use Arrays.fill, and finally convert to a String
2. Iterate through a loop adding a space each time
3. Use String.format

Solution 4

String text = "text";
text += new String(" ");

View more solutions

Comments

[matbrgz]

Add some examples of "before" and "after".

[Zoe stands with Ukraine]

If you had read the entire question, you would have seen: Note: " " is not the solution.

[surendrapanday]

The length of the character and space is different, How can I ensure same length?

[brady]

@surendrapanday I’m sorry but I don’t understand your question. Can you explain more? Maybe an example?

[surendrapanday]

This solution produces correct output in the console, but when using the same string in BufferedImage to create Image from the string, this produce output something. aaa : bbb mmm : ccc

[brady]

@surendrapanday That will depend very much on the Graphics calls you make to render the buffered image. To render an image of formatted text, I would probably explore using Swing components with a layout to do the painting. That's outside the scope of this question and answer, but if you ask a new question, you could link it here.

[surendrapanday]

If I use swing component then will there be any behavior change on the different platform (like Andriod, Windows, Mac, etc)