The replaceAll() method accepts a regular expression and a String as parameters and, matches the contents of the current string with the given regular expression, in case of match, replaces the matched elements with the String.
To delete a particular String from a file using the replaceAll() method −
Retrieve the contents of the file as a String.
Replace the required word with an empty String using the replaceAll() method.
Rewrite the resultant string into the file again.
Example
import java.io.File; import java.io.FileNotFoundException; import java.io.PrintWriter; import java.util.Scanner; public class StringExample { 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 FileNotFoundException { String filePath = "D://sample.txt"; String result = fileToString(filePath); System.out.println("Contents of the file: "+result); //Replacing the word with desired one result = result.replaceAll("\\bTutorialspoint\\b", ""); //Rewriting the contents of the file PrintWriter writer = new PrintWriter(new File(filePath)); writer.append(result); writer.flush(); System.out.println("Contents of the file after replacing the desired word:"); System.out.println(fileToString(filePath)); } }
Output
Contents of the file: Hello how are you welcome to Tutorialspoint Contents of the file after replacing the desired word: Hello how are you welcome to