Convert byte[] array to File using Java

Last Updated : 11 Dec, 2018

To convert byte[] to file getBytes() method of String class is used, and simple write() method can be used to convert that byte into a file.

Program 1: Convert a String into byte[] and write in a file.

// Java Program to convert 
// byte array to file 
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.OutputStream; 
  
public class GFG { 
  
    // Path of a file 
    static String FILEPATH = ""; 
    static File file = new File(FILEPATH); 
  
    // Method which write the bytes into a file 
    static void writeByte(byte[] bytes) 
    { 
        try { 
  
            // Initialize a pointer 
            // in file using OutputStream 
            OutputStream 
                os 
                = new FileOutputStream(file); 
  
            // Starts writing the bytes in it 
            os.write(bytes); 
            System.out.println("Successfully"
                               + " byte inserted"); 
  
            // Close the file 
            os.close(); 
        } 
  
        catch (Exception e) { 
            System.out.println("Exception: " + e); 
        } 
    } 
  
    // Driver Code 
    public static void main(String args[]) 
    { 
  
        String string = "GeeksForGeeks"
                        + " - A Computer Science"
                        + " Portal for geeks"; 
  
        // Get byte array from string 
        byte[] bytes = string.getBytes(); 
  
        // Convert byte array to file 
        writeByte(bytes); 
    } 
} 

Output:

Successfully byte inserted

Program 2: To Write Integer, Double, Character Value in the File (using Wrapper Class).

// Java Program to convert 
// int, char and double into bytes 
// and write it in a file 
  
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.OutputStream; 
  
public class GFG { 
  
    // Path of a file 
    static String FILEPATH = ""; 
    static File file = new File(FILEPATH); 
  
    // Method which write the bytes into a file 
    static void writeByte(byte[] byteInt, 
                          byte[] byteChar, byte[] byteDouble) 
    { 
  
        try { 
  
            // Initialize a pointer in file using OutputStream 
            OutputStream os = new FileOutputStream(file); 
  
            // Starts writing the bytes in it 
  
            // Write int value 
            os.write(byteInt); 
  
            // Write char value 
            os.write(byteChar); 
  
            // Write double value 
            os.write(byteDouble); 
  
            System.out.println("Successfully byte inserted"); 
  
            // Close the file 
            os.close(); 
        } 
  
        catch (Exception e) { 
            System.out.println("Exception: " + e); 
        } 
    } 
  
    // Driver Code 
    public static void main(String args[]) 
    { 
        int num = 56; 
        char ch = 's'; 
        double dec = 78.9; 
  
        // Insert int value 
        byte[] byteInt = Integer.toString(num).getBytes(); 
  
        // Insert char value 
        byte[] byteChar = Character.toString(ch).getBytes(); 
  
        // Insert double value 
        byte[] byteDouble = Double.toString(dec).getBytes(); 
  
        writeByte(byteInt, byteChar, byteDouble); 
    } 
} 

Output:

Successfully byte inserted

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