For a number of reasons, you might need to write an object to a file for future usage. Perhaps your applet needs to keep some sort of “state” and between invocations, it needs to recall a “state” object, or you have a number of different applets that all share data but need a way to do so indirectly without using RMI or CORBA.

A method to accomplish all of the above is to take an object and write it to a file for later retrieval and re-creation.

Here is some sample code that will write an object to a file:

 import java.io.File;import java.io.FileOutputStream;import java.io.ObjectOutputStream;import java.io.IOException;public class WriteObjectToFile  public void writeObject(String filename, Object obj)    File objFile = new File(filename);    try      FileOutputStream fos = new FileOutputStream(objFile);      ObjectOutputStream oos = new ObjectOutputStream(fos);      oos.writeObject(obj);      oos.close();    }    catch (IOException e)      System.out.println();    }  }  public static void main (String args[])    WriteObjectToFile objectWriter = new WriteObjectToFile();    Object localObj = new Object();    String test = "This will appear in the file";    localObj = (object)test;    objectWriter.writeObject("appletFile.obj", localObj);  }}

Using this, you can store the value of any object to a file. As in the example [appletFile.obj], the file will contain the value of [test] object.