File Read & Write

[Lomanu4]

In Java, file reading and writing can be done efficiently using buffered streams, readers, and writers. Here's a short explanation with examples:

1. Buffered File Reading (Using BufferedReader)


Buffers data for efficient reading (instead of byte-by-byte).


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

public class ReadFile {
public static void main(String[] args) {
try (BufferedReader reader = new BufferedReader(new FileReader("file.txt"))) {
String line;
while ((line = reader.readLine()) != null) { // Reads line-by-line
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
2. Buffered File Writing (Using BufferedWriter)


Buffers data for efficient writing.


import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class WriteFile {
public static void main(String[] args) {
try (BufferedWriter writer = new BufferedWriter(new FileWriter("output.txt"))) {
writer.write("Hello, Java!");
writer.newLine(); // Adds a newline
} catch (IOException e) {
e.printStackTrace();
}
}
}
3. Key Classes

Class	Purpose
FileReader / FileWriter	Reads/Writes characters (text files).
BufferedReader / BufferedWriter	Wraps readers/writers for buffered I/O.
FileInputStream / FileOutputStream	Reads/Writes bytes (binary files).
Scanner	Alternative for reading text (e.g., new Scanner(new File("file.txt"))).

4. Try-with-Resources

• Automatically closes files (no need for finally blocks).
• Used in the examples above (try (BufferedReader ...)).

When to Use?

• Use BufferedReader/BufferedWriter for text files.
• Use FileInputStream/FileOutputStream for binary files (images, etc.).
• Use Scanner for parsing structured text.

Let me know if you'd like a deeper explanation! ?

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