Java.io.BufferedWriter class in Java

The BufferedWriter class in Java is used to write text efficiently to character-based output streams. It stores characters in a buffer before writing them to the destination, thereby reducing the number of I/O operations and improving performance.

• Faster Writing: Writes large chunks of data at once instead of writing character by character.
• Easy to Use: Provides methods like write() and newLine() to simplify text output.

Class Declaration 

public class BufferedWriter extends Writer

BufferedWriter class extends the Writer class, meaning it is a subclass specialized for buffered character output operations.

Example: Writing Text to a File

import java.io.*;

public class GFG{
    
    public static void main(String[] args){
        
        try {
            BufferedWriter writer = new BufferedWriter(
                new FileWriter("output.txt"));

            writer.write("Hello, World!");
            writer.newLine();
            writer.write(
                "This is written using BufferedWriter.");

            writer.close();
            System.out.println(
                "File written successfully.");
        }
        catch (IOException e) {
            System.out.println("An error occurred: "
                               + e.getMessage());
        }
    }
}

File written successfully.

Explanation: This program creates a BufferedWriter that wraps a FileWriter to write text efficiently to output.txt. The write() method writes text, and newLine() inserts a line break.

Constructors of BufferedWriter Class

1. BufferedWriter(Writer out): Creates a buffered character output stream using the specified writer.

BufferedWriter bw = new BufferedWriter(new FileWriter("file.txt"));

2. BufferedWriter(Writer out, int size): Creates a buffered character output stream with a custom buffer size.

BufferedWriter bw = new BufferedWriter(new FileWriter("file.txt"), 8192);

Example: Writing User Input to a File

import java.io.*;

public class GFG{
    
    public static void main(String[] args)
        throws IOException{
            
        BufferedReader reader = new BufferedReader(
            new InputStreamReader(System.in));

        System.out.print("Enter text to save in file: ");
        String text = reader.readLine();

        BufferedWriter writer = new BufferedWriter(
            new FileWriter("output.txt"));

        writer.write(text);
        writer.close();

        System.out.println(
            "Text written successfully to userInput.txt");
    }
}

Output:

output.txt:

Methods in BufferedWriter class