1. Introduction to File Handling

1.1 What is File Handling

File handling is the process of reading from and writing to files.

1.2 Why File Handling

Stores data permanently
Useful for large data storage
Enables data sharing between programs

1.3 Types of Files

Text files → readable content
Binary files → non-readable format

1.4 Java Package

Java provides java.io package for file handling.

2. Reading Files

2.1 Using FileReader

import java.io.FileReader;FileReader fr = new FileReader("file.txt");
int ch;
while ((ch = fr.read()) != -1) {
    System.out.print((char) ch);
}
fr.close();

2.2 Using Scanner

import java.io.File;
import java.util.Scanner;Scanner sc = new Scanner(new File("file.txt"));
while (sc.hasNextLine()) {
    System.out.println(sc.nextLine());
}
sc.close();

2.3 Key Points

Always close file
Handle exceptions

3. Writing Files

3.1 Using FileWriter

import java.io.FileWriter;FileWriter fw = new FileWriter("file.txt");
fw.write("Hello World");
fw.close();

3.2 Appending Data

FileWriter fw = new FileWriter("file.txt", true);
fw.write("New Data");
fw.close();

3.3 Important Notes

Use close() to save data
Use flush() if needed

4. File Streams

4.1 What are Streams

Streams are sequences of data.

4.2 Byte Streams

Used for binary data:

FileInputStream fis = new FileInputStream("file.txt");

4.3 Character Streams

Used for text data:

FileReader fr = new FileReader("file.txt");

4.4 Difference

Byte Stream	Character Stream
Binary data	Text data
InputStream	Reader

5. Buffered Readers and Writers

5.1 BufferedReader

import java.io.*;BufferedReader br = new BufferedReader(new FileReader("file.txt"));
String line;while ((line = br.readLine()) != null) {
    System.out.println(line);
}
br.close();

5.2 BufferedWriter

BufferedWriter bw = new BufferedWriter(new FileWriter("file.txt"));
bw.write("Hello Buffered");
bw.close();

5.3 Advantages

Faster performance
Efficient reading/writing
Reads large data easily

Conclusion

File handling is an essential concept in Java that allows programs to interact with external files for data storage and retrieval. By understanding file reading, writing, streams, and buffering techniques, beginners can build real-world applications that manage data efficiently.

File Handling