How to read the all objects in file after I write all the files

Question

I am trying to do a program that can read all the objects that I put into the file. The input works well and I put 8 objects in, But when I try to read them from the file,It shows the java.io.StreamCorruptedException, It seems it can not display the all methods I entered. I don't know where I do wrong. Is there any other way to realize the function that display every objects in the system. Thanks And I search the solution Appending to an ObjectOutputStream but I can't understand the answer,I will very appreciate it if someone can explain it

import java.util.*;
import java.io.*;
public class driver
{
    public static void main(String[] args) 
    {
        Scanner keyboard = new Scanner(System.in);
        ObjectOutputStream objOut = null;
        ObjectInputStream objIn = null;
        Pet p = null;
        Person owner = null;

        do{
            System.out.println("what u want to do");
            System.out.println("1.add the pet\n2read the pet\n3get the weight\n4 system exit");
            int option = keyboard.nextInt();
            keyboard.nextLine();

            switch(option)
            {
            case 1:
                try 
                {
                    objOut = new ObjectOutputStream(new FileOutputStream("pet.dat",true));
                    owner = new Person();
                    owner.getInput();
                    System.out.println("Type of pet?(1-Mammal;2-Fish;3-Amphibian");
                    int type = keyboard.nextInt();
                    keyboard.nextLine();
                    switch (type)
                    {
                    case 1:
                        p = new Mammal();
                        p.owner = owner;
                        p.getInput();
                        objOut.writeObject(p);
                        objOut.close();
                        break;
                    case 2:
                        p = new Fish();
                        p.owner = owner;
                        p.getInput();
                        objOut.writeObject(p);
                        objOut.close();
                        break;
                    case 3:
                        p = new Amphibian();
                        p.owner = owner;
                        p.getInput();
                        objOut.writeObject(p);
                        objOut.close();
                        break;
                    }
                } 

                catch (Exception e) 
                {
                    e.printStackTrace();
                    System.out.println("here");
                }

                break;

            case 2:
                try 
                {
                    objIn = new ObjectInputStream(new FileInputStream("pet.dat"));

                    try 
                    {
                        while(true)
                        {
                            p = (Pet)objIn.readObject();
                            System.out.println(p);
                        }

                    } 
                    catch (EOFException e) 
                    {
                        System.out.println("System ends");
                    }
                } 

                catch (Exception e)
                {
                    e.printStackTrace();

                    System.out.println("something in driver");
                }

                break;

            case 3:
                try 
                {
                    objIn = new ObjectInputStream(new FileInputStream("pet.dat"));

                    try 
                    {
                        while(true)
                        {
                            p = (Pet)objIn.readObject();
                            System.out.println(p.getname() + "'s weight is: " + p.getweight());
                        }

                    } 
                    catch (EOFException e) 
                    {
                        System.out.println("System ends");
                    }
                } 

                catch (Exception e)
                {
                    e.printStackTrace();
                    System.out.println("something in driver");
                }
                break;

            case 4:

                System.exit(0);
            }
        }while(true);
    }
}

Whether your program is throwing some error ? have a look at the Serialization technique to get the solution — Shirishkumar Bari, Apr 18 '14 at 07:59
no error, but the exception said java.io.StreamCorruptedException — xiaopassion, Apr 18 '14 at 08:01
Show your logcat that details the **java.io.StreamCorruptedException** that is the StackTrace.For detailed research. — ShihabSoft, Apr 18 '14 at 08:50
You don't consider StreamCorruptedException to be an error? You're 100% wrong about that. You should have posted the stack trace in your question. — user207421, Apr 18 '14 at 10:05

score 0 · Answer 1 · edited May 23 '17 at 11:49

objOut = new ObjectOutputStream(new FileOutputStream("pet.dat",true));

You can't append to object stream files, at least not without special measures. You get 'StreamCorruptedException: invalid type code AC', which is indeed both an exception and an error, contrary to your apparent belief as expressed in your comment. Duplicate of hundreds of questions here on that topic. See here for a full explanation.

How to read the all objects in file after I write all the files

1 Answers1