Reading and Writing on File using FileInputStream and FileOutputStream Class in Java

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In this lesson, you will learn.

• Reading and Writing Files
• Example

I/O Stream Classes

The following is the I/O stream hierarchy.

Byte Stream

In Java, byte streams are used to perform input and output of bytes or binary data, making them very useful for handling raw binary data and files such as images, audio files, and any other binary data files.

The following are the two primary byte stream classes

• FileInputStream: It reads data from a file in a sequence of bytes. It is useful for reading byte-oriented data such as binary files.
• FileOutputStream: It writes data to a file in a sequence of bytes. It is used for writing raw bytes such as image data.

Example: Copying a File Using Byte Streams

Below is an example demonstrating that reading from one file and writing to another using byte streams in Java. This example effectively copies a file.

package bytestream;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class FileCopy {
    public static void main(String[] args) {
    	
        /* Using try-with-resources to ensure that all resources 
         * will be closed automatically */
        try (FileInputStream in = new FileInputStream
        		("src/bytestream/file1.txt");
             FileOutputStream out = new FileOutputStream
            		 ("src/bytestream/file2.txt")) {
            
            int byteRead;

            // Read a single byte at a time and write it to the output file
            while ((byteRead = in.read()) != -1) {
                out.write(byteRead);
            }
            
            System.out.println("File has been copied.");
        } catch (IOException e) {
            System.out.println("Error occurred:");
            e.printStackTrace();
        }
    }
}

Output

File has been copied.

Difference b/w Byte and Character Stream Classes

ByteStream

Byte streams in Java handle I/O of raw binary data. They read or write data byte by byte, which makes them suitable for handling all types of data, including binary files (like images, audio files, etc.) and textual data.

Character Stream

Character streams handle the I/O of characters, automatically taking character encoding into account. They read or write data character by character.

This abstraction is beneficial when dealing with textual data as it seamlessly handles character encoding, converting internally between characters and bytes.

Thus, character streams are preferred when working with text files.

Key Differences

End of the lesson….enjoy learning

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