The Java.io.FileOutputStream can used to convert an array of bytes into a file. In this example, you read a file from “C:\\testing.txt“, and convert it into an array of bytes, and write it into another file “C:\\testing2.txt“.

package com.mkyong.common;
 
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
 
public class ArrayOfBytesToFile
{
    public static void main( String[] args )
    {
    	FileInputStream fileInputStream=null;
 
        File file = new File("C:\\testing.txt");
 
        byte[] bFile = new byte[(int) file.length()];
 
        try {
            //convert file into array of bytes
	    fileInputStream = new FileInputStream(file);
	    fileInputStream.read(bFile);
	    fileInputStream.close();
 
	    //convert array of bytes into file
	    FileOutputStream fileOuputStream = 
                  new FileOutputStream("C:\\testing2.txt"); 
	    fileOuputStream.write(bFile);
	    fileOuputStream.close();
 
	    System.out.println("Done");
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}
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