How to serialize ArrayList of objects?
arraylist, extend, java, serialization, subclass
Solution
You can serialize class of ArrayList like this
public class MyData implements Serializable {
private long id;
private String title;
private ArrayList<String> tags;
...
public String getTitle() {
}
}
And to create serializable
ArrayList<MyData> myData = new ArrayList<MyData>();
try{
// Serialize data object to a file
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("MyData.ser"));
out.writeObject(myData);
out.close();
// Serialize data object to a byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream() ;
out = new ObjectOutputStream(bos) ;
out.writeObject(myData);
out.close();
// Get the bytes of the serialized object
byte[] buf = bos.toByteArray();
} catch (IOException e) {
}
Problem
I want to serialize an arraylist of Item but it doesn't work.... my Item class extends Stuff class and has some subclasses. all of my classes implement Serilalizable. i have this part : ``` try{ // Serialize data object to a file ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("MyData.ser")); out.writeObject(myData); out.close(); // Serialize data object to a byte array ByteArrayOutputStream bos = new ByteArrayOutputStream() ; out = new ObjectOutputStream(bos) ; out.writeObject(myData); out.close(); // Get the bytes of the serialized object byte[] buf = bos.toByteArray(); } catch (IOException e) { } ``` my classes : ``` public class Stuff implements Serializeable{ .... some protected fields . . } public class Item extends Stuff implements Serializable{ ... .. . } and some subclasses of Item: public class FirstItem extends Item implements Serializable{ ... } public class SecondItem extends Item implements Serializable{ ... } ... I want to serialize an object contains ArrayList of <Item> that has objects of Item's subclasses (FirstItem,SecondItem,...) ``` i think informations are sufficient... it's just a little mistake and now works correctly... I'm sorry for my stupid question. Thank you for your answers.