The StringUtils class of org.apache.commons.lang3 package of Apache commons library provides a method named containsIgnoreCase().
This method accepts two String values representing a source string and search string respectively, verifies whether the source string contains the search string ignoring the case. It returns a boolean value which is −
true, if the source string contains the search string.
false, if the source string does not contain the search string.
To find whether a String contains a particular sub string irrespective of case −
Add the following dependency to your pom.xml file
<dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.9</version> </dependency>
Get the source String.
Get the search String.
Invoke the containsIgnoreCase() method by passing above two string objects as parameters (in the same order).
Example
Assume we have a file named sample.txt in the D directory with the following content −
Tutorials point originated from the idea that there exists a class of readers who respond better to on-line content and prefer to learn new skills at their own pace from the comforts of their drawing rooms. At Tutorials point we provide high quality learning-aids for free of cost.
Example
Following Java example reads a sub string from the user and verifies whether the file contains the given sub string irrespective of case.
import java.io.File; import java.util.Scanner; import org.apache.commons.lang3.StringUtils; public class ContainsIgnoreCaseExample { public static String fileToString(String filePath) throws Exception { String input = null; Scanner sc = new Scanner(new File(filePath)); StringBuffer sb = new StringBuffer(); while (sc.hasNextLine()) { input = sc.nextLine(); sb.append(input); } return sb.toString(); } public static void main(String args[]) throws Exception { Scanner sc = new Scanner(System.in); System.out.println("Enter the sub string to be verified: "); String subString = sc.next(); String fileContents = fileToString("D:\\sample.txt"); //Verify whether the file contains the given sub String boolean result = StringUtils.containsIgnoreCase(fileContents, subString); if(result) { System.out.println("File contains the given sub string."); }else { System.out.println("File doesnot contain the given sub string."); } } }
Output
Enter the sub string to be verified: comforts of their drawing rooms. File contains the given sub string.