Comparing Strings While Ignoring Whitespace in Java

Compare Strings While Ignoring Whitespace in Java

Comparing strings while ignoring whitespace in Java can be quite tricky. There are several approaches to this task, and we'll walk you through the most common solutions. The primary goal of a string comparison is to determine whether two strings are equal or not. If whitespace has been inserted, deleted, or changed, the result of the comparison should be false. We'll demonstrate a few different methods for comparing strings in Java while ignoring whitespace.

Using Regular Expression

The most straightforward way of comparing strings while ignoring whitespace is to use a regular expression. With a simple expression, you can check whether two strings are equal without having to worry about whitespace. Here's an example of a regular expression that checks if two strings are equal, disregarding any whitespace:

String regex = "\\s*(.*?)\\s*";
if(s1.matches(regex) && s2.matches(regex) && s1.equalsIgnoreCase(s2)) {
    // Strings are equal
}

This code works by first replacing any whitespace characters with an empty string. Then, it compares the two strings, ignoring any differences in case. If the strings match, the "Strings are equal" part of the code will be executed.

Using StringUtils Class

Another way of comparing strings while ignoring whitespace is to use the Apache Commons Lang library. This library provides several utility classes for working with strings and other objects in Java. One of these classes is the StringUtils class, which contains the equalsIgnoreWhitespace() method. This method compares two strings, disregarding any whitespace characters. Here's an example of how to use this class to compare two strings:

if(StringUtils.equalsIgnoreWhitespace(s1, s2)) {
    // Strings are equal
}

This code works by first replacing any whitespace characters with an empty string. It then compares the two strings and returns true if they are equal. If the strings are not equal, it will return false.

Conclusion

Comparing strings while ignoring whitespace in Java is a tricky task. Fortunately, there are several methods available for performing this task. We've demonstrated the two most common solutions: using a regular expression and using the Apache Commons Lang library. Whichever approach you decide to use, make sure you test it thoroughly before deploying your code.