Deserialize only if a serialized file exists

Question

I have my program setup to serialize a certain Facebook Object on exit, and deserialize it on open. But I want to have an if statement in the deserialization portion to only go on with it if a serilization file is present to avoid errors. How can I do that? Is there anyway that I could refer to the file "serilaized" and check if it exists?

Deserialization portion:

Facebook facebook = null;

    try {
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(
                "serialized"));

        facebook = (Facebook) ois.readObject();

        ois.close();
    } catch (FileNotFoundException e) {
        System.err.println("Could not open the file \"serialized\"");
    } catch (IOException e) {
        System.err.println("Could not de-serialize the object");
    } catch (ClassNotFoundException e) {
        System.err.println("Could not cast the de-serialized object");
    }

Serialization portion:

try {
                ObjectOutputStream oos = new ObjectOutputStream(
                        new FileOutputStream ("serialized"));

                oos.writeObject(facebook);
                oos.close();
            } catch (FileNotFoundException e) {
                System.err
                        .println("Could not create the file \"serialized\"");
            } catch (IOException e) {
                System.err.println("Could not serialize the object");
            }

possible duplicate of [How do I check if a file exists in Java?](http://stackoverflow.com/questions/1816673/how-do-i-check-if-a-file-exists-in-java) — fabian, Sep 20 '15 at 22:21

score 1 · Accepted Answer · answered Sep 20 '15 at 22:20

1

The FileNotFoundException should catch the case where there is no file present to deserialize. Throwing the error is fine, so long as it is handled gracefully.

answered Sep 20 '15 at 22:20

Beryllium

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But i want the if statement because I want to do another action if the serialized file does not exist – shishi Sep 20 '15 at 22:21
In the `catch` statement simply put the code you want executed in case the file doesn't exist. – Beryllium Sep 20 '15 at 22:22
Hmm yes that does make sense. Thanks a lot :) – shishi Sep 20 '15 at 22:23
It doesn't work because i want to make a new Facebook object if the serialized file doesn't exist, and it needs to have the same name "facebook". I can't use that name because of duplicate variables. – shishi Sep 20 '15 at 22:26
Is there anyway that I could refer to the file "serilaized" and check if it exists? – shishi Sep 20 '15 at 22:30
You can reuse the variable. `facebook = ...` – Beryllium Sep 20 '15 at 22:31
Oh yes, I forgot about that. Thanks that solved everything now :) – shishi Sep 20 '15 at 22:45

Deserialize only if a serialized file exists

1 Answers1