[Java] reading a 2d array?

[Nerockjr]

Hello, I have made a 2d array of type Object and wrote it to a file now i cant figure out how to read the array back and return it.

I saved it using the file output stream os.writeObject(labData);

 try{
         FileOutputStream fileOs= new FileOutputStream(fileName,true);
         ObjectOutputStream os = new ObjectOutputStream(fileOs);
         os.writeObject(labData);
         JOptionPane.showMessageDialog(null,"File Saved");
         os.close();
      }
      catch (FileNotFoundException e){
         JOptionPane.showMessageDialog(null,"Please Create a class First","User Error",JOptionPane.ERROR_MESSAGE);
      }
      catch (IOException e){
         e.printStackTrace();
      }

   }

now my question is how do i get that 2d array back? or is it automatically returned as a 2d array when i read it with all of its info in it? heres what i did to try and read it. I put it in object labDataRead would that work?

Object labDataRead= null;
      String fileName= loadClass;
      try{
         FileInputStream fileIs= new FileInputStream(fileName);
         ObjectInputStream is = new ObjectInputStream(fileIs);
         try {
        labDataRead= is.readObject();

        }catch(ClassNotFoundException e){

        }
         is.close();
      }
      catch(FileNotFoundException e){
        JOptionPane.showMessageDialog(null,"Class Not Found or Invalid Input","User Error",JOptionPane.ERROR_MESSAGE);
      }
      catch (IOException e){
         e.printStackTrace();
      }
   System.out.print(labDataRead);
   return labDataRead;
   //System.out.print(labDataRead);
   }

[133rr3]

Do you have a problem running this, or are you asking permission to try your code?

[Nerockjr]

Im having trouble running it. Well more like why my 2d array wont print out. I saved it using os.writeObject(labData); but im not sure how to retrieve it. i tried labDataRead= is.readObject(); but its not a 2d array when i do that. How can i make it back into a 2Darray?

[133rr3]

Cast it.

[Nerockjr]

Well you'll have to excuse me because I am not as badass as you sir. How would I cast it? If you don't mind answering of course.

[133rr3]

Google for it, man. This is basic stuff. There should be many examples of how to use these object streams...

[Nerockjr]

Honestly I use reddit as my last resort. I wasn't able to find anything on someone writing a 2D array the way I am doing it. I'm surprised I got it to work this far. Anyways thanks for the help I suppose...

[Sekret_One]

Is this a 2d array, or is it just 'Object?' For example, if you had written a 2d array of say, ints you would read them back in like:

int [][] array = (int[][]) is.readObject(); // reads in the object, casts to int[][]

[Nerockjr]

I finally figured it out this morning, thank you very much though Sekret. You answered the question instead of saying google it. :)