writing arraylist of objects in file

Question

I want to write arraylist of objects in a file. But only one object in going in file.Atfirst I am fetching all the stored objects and then appending new object after that I write whole arrayList to the file.

Here is my code....

public void write(UserDetail u1) throws FileNotFoundException {
    ArrayList<UserDetail> al = new ArrayList<UserDetail>();
    FileInputStream fin = new FileInputStream(FILEPATH);

    try {

        if (fin.available() != 0) {
            ObjectInputStream ois = new ObjectInputStream(fin);
            while (fin.available() != 0 && ois.available() != 0) {
                try {
                    al.add((UserDetail) ois.readObject());

                } catch (ClassNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {

                    if (ois != null) {
                        ois.close();

                    }
                }
            }
        }
        al.add(u1);
        FileOutputStream fos = new FileOutputStream(FILEPATH);
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(al);
        oos.flush();
        oos.close();
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        throw e;
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

help me......thnx in advance

Can you show , where do you call this function, and where you initialize your object that you pass as an argument to this function. — Prateek
– Prateek, Commented Feb 18, 2013 at 12:39

Mikhail Vladimirov · Accepted Answer · 2013-02-18 12:39:15Z

1

You are reading object of type UserDetail but writing object of type ArrayList. Should probably be:

al = (ArrayList)ois.readObject ();

instead of

al.add ((UserDetail) ois.readObject ());

answered Feb 18, 2013 at 12:39

Mikhail Vladimirov

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