txtToBin

import java.io.*;
import java.nio.ByteBuffer;
public class App {

    public static void main(String[] args) {
        File textFile = new File("textFile.txt");
        File binFile = new File("binFile.bin");
        writeStudentToText(new Student("Petar", "04323", 5, 21), textFile);
        Student student = readStudentFromText(textFile);
        System.out.println("INFO FROM TXT FILE:");
        student.printInfo();
        writeStudentToBin(student, binFile);
        System.out.println("INFO FROM BIN FILE:");
        student = readStudentFromBin(binFile);
        student.printInfo();
    }


    public static void writeStudentToText(Student student, File textFile){
        FileWriter fileWriter = null;
        try {
            fileWriter = new FileWriter(textFile);
            fileWriter.write(student.getName() + "|" + student.getFacNumber() + "|" + student.getGrade() + "|" + student.getAge());
            fileWriter.flush();
        } catch (IOException e) {
            System.out.println("There was an IO error with writing Student to Text!");
            e.printStackTrace();
        } finally {
            if(fileWriter != null) try{
                fileWriter.close();
            } catch (IOException e) {
                System.out.println("Can't close fileWriter(IO error)!");
                e.printStackTrace();
            }
        }

    }

    public static Student readStudentFromText(File textFile) {
        try {
            BufferedReader bf = new BufferedReader(new FileReader(textFile));
            String line = bf.readLine();
            String[] info = line.split("\\|", 4);
            Student student = new Student(info[0], info[1], Double.parseDouble(info[2]), Integer.parseInt(info[3]));
            bf.close();
            return student;
        } catch (IOException e) {
            System.out.println("There was an IO error with reading Student from Text");
            e.printStackTrace();
            return null;
        }
    }

    public static void writeStudentToBin(Student student, File binFile){
        byte[] sName = student.getName().getBytes();
        byte[] sFacNumber = student.getFacNumber().getBytes();
        byte[] sGrade = ByteBuffer.allocate(Double.BYTES).putDouble(student.getGrade()).array();
        byte[] sAge = ByteBuffer.allocate(Integer.BYTES).putInt(student.getAge()).array();
        try {
            FileOutputStream os = new FileOutputStream(binFile);
            os.write(sFacNumber.length);
            os.write(sFacNumber);
            os.write(sName.length);
            os.write(sName);
            os.write(sGrade);
            os.write(sAge);
            os.flush();
            os.close();
        } catch (FileNotFoundException e) {
            System.out.println("Bin File not found");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("There was an IO error with writing Student to Bin!");
            e.printStackTrace();
        }
    }

    public static Student readStudentFromBin(File binFile){
        try {
            FileInputStream is = new FileInputStream(binFile);
            byte[] facNum = new byte[is.read()];
            is.read(facNum);
            byte[] name = new byte[is.read()];
            is.read(name);
            byte[] grade = new byte[Double.BYTES];
            is.read(grade);
            byte[] age = new byte[Integer.BYTES];
            is.read(age);
            is.close();
            return new Student(new String(name), new String(facNum), ByteBuffer.wrap(grade).getDouble(), ByteBuffer.wrap(age).getInt());
        } catch (FileNotFoundException e) {
            System.out.println("Bin File not found");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("There was an IO error with reading Student to Bin!");
            e.printStackTrace();
        }
        return null;
    }
}