Unlocking the Secrets of File Reading in Java

Streamlined Reading with BufferedInputStream

One of the most effective ways to read files is by leveraging the BufferedInputStream class. This powerful tool allows us to read each line from a file with ease.

import java.io.BufferedReader;
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;

public class ReadFileWithBufferedInputStream {
    public static void main(String[] args) {
        try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream("input.txt"))) {
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = bis.read(buffer))!= -1) {
                System.out.write(buffer, 0, bytesRead);
            }
        } catch (IOException e) {
            System.err.println("Error reading file: " + e.getMessage());
        }
    }
}

In this example, we’ve successfully utilized BufferedInputStream to read each line from the file. Note that to run this file, you’ll need to have an input.txt file in your current working directory.

Efficient Reading with BufferedReader

Another approach to reading files is by employing the BufferedReader class. This class provides a convenient way to read a file line by line.

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class ReadFileWithBufferedReader {
    public static void main(String[] args) {
        try (BufferedReader br = new BufferedReader(new FileReader("input.txt"))) {
            String line;
            while ((line = br.readLine())!= null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            System.err.println("Error reading file: " + e.getMessage());
        }
    }
}

As we can see, BufferedReader makes quick work of reading the file.

Scanning Files with Ease

Our third example introduces the Scanner class, which offers a more flexible way to read files. By creating a File object and associating it with a Scanner object, we can tap into the file’s contents.

The Scanner class provides several useful methods, including:

• hasNextLine(): Returns true if there’s a next line in the file
• nextLine(): Returns the entire line from the file

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ReadFileWithScanner {
    public static void main(String[] args) {
        try (Scanner scanner = new Scanner(new File("input.txt"))) {
            while (scanner.hasNextLine()) {
                System.out.println(scanner.nextLine());
            }
        } catch (FileNotFoundException e) {
            System.err.println("Error reading file: " + e.getMessage());
        }
    }
}

By mastering these techniques, you’ll be well-equipped to tackle even the most complex file-reading tasks in Java.