How to Use Regular Expressions in the String.contains() Method in Java?

How can I utilize regular expressions to check if a String contains specific words in a certain order in Java?

String str = "The store has various products";
boolean contains = str.contains("stores") && str.contains("store") && str.contains("product");

In Java, the String.contains() method does not support regular expressions. To check if a string contains multiple words in a specified order, you need to employ the Pattern and Matcher classes from the java.util.regex package.

import java.util.regex.*;

String input = "Our stores offer the best product selection";
Pattern pattern = Pattern.compile("stores.*store.*product");
Matcher matcher = pattern.matcher(input);
boolean found = matcher.find(); // true if the pattern is found

Causes

• String.contains() is designed for simple substring checks and does not interpret regex syntax.
• Attempting to use multiple .contains() calls does not ensure the words are in order or appropriately spaced.

Solutions

• Use the Pattern and Matcher classes to create a regex that defines the sequence and arrange the words properly with regex syntax.
• Alternatively, build a regex string to match the order of your desired terms with any intervening characters. Example: `"stores.*store.*product"`.

Mistake: Using String.contains() for regex pattern matching.

Solution: Instead, utilize Pattern and Matcher to effectively work with regex.

Mistake: Forgetting to escape special regex characters in your patterns.

Solution: Use double backslashes (\\) to escape special characters in your regex.