Lecture 94:-  File handling

File handling in Java refers to the process of reading data from files or writing data to files. Java provides several classes and methods in its standard library to perform file handling operations, making it easy to work with files in a platform-independent manner.

Key classes for file handling in Java include:

1. File:
   • The File class represents a file or directory path on the file system.
   • It provides methods to check if a file exists, get its name, check if it's a directory, and more.
2. FileInputStream and FileOutputStream:
   • The FileInputStream class is used to read data from a file, while FileOutputStream is used to write data to a file.
   • These classes are used for byte-level file handling.
3. BufferedReader and BufferedWriter:
   • BufferedReader and BufferedWriter classes are used for character-level file handling.
   • They provide buffering, which improves the performance of file I/O operations.
4. FileReader and FileWriter:
   • FileReader and FileWriter classes are used to read and write text files.
   • They are higher-level abstractions of FileInputStream and FileOutputStream, and they work with characters instead of bytes.

Here's a simple example of reading and writing data to a file in Java:

javaCopy code

import java.io.*; public class FileHandlingExample {    public static void main(String[] args) {        // Writing data to a file        try (FileWriter writer = new FileWriter("data.txt")) {            writer.write("Hello, this is a sample text.\n");            writer.write("Writing data to a file in Java.");        } catch (IOException e) {            e.printStackTrace();        }        // Reading data from a file        try (BufferedReader reader = new BufferedReader(new FileReader("data.txt"))) {            String line;            while ((line = reader.readLine()) != null) {                System.out.println(line);            }        } catch (IOException e) {            e.printStackTrace();        }    } }

In this example, the program writes two lines of text to a file named "data.txt" using FileWriter. Then, it reads the content of the file line by line using BufferedReader and displays it on the console.

When working with file handling operations in Java, it's essential to handle exceptions properly, close the file resources after usage (using try-with-resources), and ensure platform independence by using appropriate methods from the File class.