In Java - How to map resultSet into a complex object?

Question

How can I map a resultset from a few tables into a complex object? let me elaborate:

Lets say I have these 2 classes:

public class User {
    private int         


        

Answer 1

Create a HashMap of where user id is the key, and user is the value. Then when you process the result set, do map.get(resultset.get(userid)), if it's null, create a new user, but if it isn't then do the logic to append a user to the country.

HashMap users;
HashMap countries;
//inside the result set processing
User u = users.get(resultSet.get("id"));
    if(null != u) {
      //populate user here
    } else {
       Country c = countries.get(resultSet.get(country);
       c.users.add(u);
    }