To convert all the capital letters in a .txt file to small letters in Java

To convert all capital letters to small letters in a “.txt “file using Java involves reading the file, converting the text to lowercase, and then writing the modified text back to the file or to a new file.

Conversion of all the capital letters in a .txt file to small letters

The following are the steps required to convert capital letters in a “.txt” file to lower case in java,

1.Reading the File: Use “FileReader” and “BufferedReader” to read the content of the file. These classes provide efficient reading of characters, arrays and lines.

2.Converting Text: Convert the text to lowercase using the “toLowerCase()” method of the “String” class. This method returns a new string with all characters converted to lowercase.

3.Writing to the file: Use “FileWriter” and “BufferedWriter” to write the modified content back to the file or to a new file. These classes provide efficient writing of characters, arrays and strings

Implementation:

import java.io.*;

public class ConvertToLowercase {
    public static void main(String[] args) {
        String inputFilePath = "input.text";
        String outputFilePath = "output.text";
        BufferedReader reader = null;
        BufferedWriter writer = null;

        try {
            reader = new BufferedReader(new FileReader(inputFilePath));
            writer = new BufferedWriter(new FileWriter(outputFilePath));
            String line;
            while ((line = reader.readLine()) != null) {
                String lowerCaseLine = line.toLowerCase();
                writer.write(lowerCaseLine);
                writer.newLine();
            }
            System.out.println("File conversion completed successfully.");
        } catch (IOException e) {
            System.err.println("An error occurred: " + e.getMessage());
        } finally {
            try {
                if (reader != null) {
                    reader.close();
                }
                if (writer != null) {
                    writer.close();
                }
            } catch (IOException e) {
                System.err.println("An error occurred while closing resources: " + e.getMessage());
            }
        }
    }
}

Key points:

• File paths : Define the paths for the input and output files. You can change ‘input.txt’ and ‘output.txt‘ to the actual file names or paths you are using
• BufferedReader  and BufferedWriter : These are used for efficient reading and writing.
• Reading and Converting : The program reads each line from the input file, converts it to lowercase using ‘tolowerCase()’, and then writes the converted line to the output file.
• Error Handling : The program includes error handling to catch and display any ‘IOException’  that might occur during file operations.
• Resource Management : The ‘finally’ block ensures that resources are properly closed, even if an error occurs.

Input and Output:

Assume the input as:

Hello Buddy!
THIS is a Task.
java programming LANGUAGE.

The Output looks as:

hello buddy!
this is a task.
java programming language.