대상에서 파일로 직접 저장하고 파일에서 대상을 읽는 방법을 어떻게 작성합니까

package date0524_data ;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;

public class Projict {
   
    public static void main(String[] args) {
        File file = new File("abc.txt");
        Student s=new Student("iteye",(byte)19,'m');
        s.writeFile(file);
        s.name="csdn";
        s.print();
        s.readFile(file);
        System.out.println("*****************");
        s.print();
    }
}
class Student
{
    public String name;// ， public
    public byte age;
    public char sex;
    public Student(String name,byte age,char sex)
    {
        this.name=name;
        this.age=age;
        this.sex=sex;
    }
    public void readFile(File f)
    {
       
        try {
            FileInputStream fis = new FileInputStream(f);
            DataInputStream dis=new DataInputStream(fis);
             name=dis.readUTF();
            age=dis.readByte();
            sex=dis.readChar();
            fis.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
       
    }
    public void writeFile(File f)
    {
        try {
            FileOutputStream fos=new FileOutputStream(f);
            DataOutputStream dos=new DataOutputStream(fos);
            dos.writeUTF(name);
            dos.write(age);
            dos.writeChar(sex);
            dos.flush();
            fos.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
       
    }
    public void print()
    {
        System.out.println("name:"+name);
        System.out.println("age:"+age);
        System.out.println("sex:"+sex);
    }
}