Storing Instances with Serialization

Question

I am making a program that needs to save objects for retrieval at a future date. The program will be given out away as a jar file to different people.

I can already store and retrieve instances of classes when giving the Object input/output stream a absolute path (String) as a parameter. I can also save images and text files in the resources folder and get it as a resource with getClass().getResource(String path).

Here is the problem: I have tried every way possible to save/get Objects to/from the resources folder. It gets really weird dealing with URLS and Files and not ordinary Strings. Can someone please help me? I need to be able to save and retrieve objects relative to the classpath so that i can access the objects when the program is a jar file saved in different paths on the computer.

Answer 1

1: resource folder (in jar), is read-only.

You can create datas, store in the jar when you package, but after, it is finished: only to read.

2: so you want user can read and write (and it is not embedded in your app).

• if it is personal datas, you can use (for PC):

  String appdata= System.getenv("APPDATA");   
  
  System.out.println(appdata);
  
  
  String dataFolder = System.getProperty("user.home") + "\\Local Settings\\ApplicationData";
  
  System.out.println(dataFolder);
  
  
  String dataFolder2 = System.getenv("LOCALAPPDATA");
  

  System.out.println(dataFolder2);

on my PC, it gives:

C:\Users\develop2\AppData\Roaming

C:\Users\develop2\Local Settings\ApplicationData

C:\Users\develop2\AppData\Local

see this: What is the cross-platform way of obtaining the path to the local application data directory?

• it is is for everybody, same principles, but you can encounter security issues

like this:

String programdata = System.getenv("PROGRAMDATA");
System.out.println(programdata);
String allusersprofile = System.getenv("ALLUSERSPROFILE");
System.out.println(allusersprofile); // same thing !
String publicdir = System.getenv("PUBLIC");
System.out.println(publicdir);