Display Data from multiple tables - jsf

Question

I'm new with JSF / Java and relational DB queries.
I'm trying to Display data from two tables in one datatable.
I have two tables tblUser and tblCity.
For These tables I've got two models Users and City.
Also got a UserDAO and a UserController.
I'd like to know how to select user data from tblUser and select City data from tblCity and Display them on my view. With MVC style.
Model:
public class User{
private Integer user_id;
private String user_name;
private Integer City_id;
//getter and setter
...
}
public class City{
private Integer city_id;
private String city_name;
//getter and setter
...
}
My Controller
#ManagedBean
#SessionScoped
public List<User> showUser(){
List<User> users = new ArrayList<>();
users= userDAO.showUserList();
return users;
}
My DAO
#ManagedBean
#RequestScoped
public class userDAO{
/**
* Creates a new instance of patientDAO
*/
private final connectToDB con = new connectToDB();
public userDAO() {
}
public List<User> showUserList() {
Connection dbConnection = null;
dbConnection = con.getDBConnection();
PreparedStatement pstmt = dbConnection
.prepareStatement("select a.user_id, a.user_name, b.city_name"
+ " from users a, cities b WHERE a.city_id = b.city_id");
ResultSet rs = pstmt.executeQuery();
List<User> users = new ArrayList<>();
List<City> cities = new ArrayList<>();
while (rs.next()) {
User user = new User();
City city = new City();
user.setUser_Id(rs.getInt("user_id"));
user.setUser_Id(rs.getString("user_name"));
city.setCity_Name(rs.getInt("city_name"));
users.add(user);
cities.add(city);
}
// close resources
rs.close();
pstmt.close();
dbConnection.close();
return users;
}
}
My View
<p:dataTable id="userDT" var="user" value="#{userController.showUserList()}">
<p:column width="200" headerText="User Name">
<h:outputText value="#{user.user_name}" />
</p:column>
<p:column width="200" headerText="City Name">
<h:outputText value="#{...}" />
</p:column>
</p:dataTable>

Answer 1

Supposing that one User has one City, you can add a city attribute to the User class:
public class User{
...
private City city;
public City getCity() {
return city;
}
public void setCity(City city) {
this.city = city;
}
...
}
In your userDAO, at the end of the while loop of the showUserList() method, put the city in the user object:
...
while (rs.next()) {
User user = new User();
City city = new City();
user.setUser_Id(rs.getInt("user_id"));
user.setUser_Id(rs.getString("user_name"));
city.setCity_Name(rs.getInt("city_name"));
user.setCity(city);
users.add(user);
}
...
The list of cities in the showUserList() method is not used outside the method, you can delete it.
And finally, edit the view like this:
...
<p:column width="200" headerText="City Name">
<h:outputText value="#{user.city.city_name}" />
</p:column>
...