How to add an object to existing List using Spring Mongo db? - spring

Question

this is class A
#Document
class User{
private String id ;
private String name;
#Dbref
private List<Socity> Socitys;
}
and this is class Socity
#Document
class Socity{
private String id ;
private String name;
}
and this is the add user function
public User addUser(User user) {
List<Socity> socity = new ArrayList<>();
user.setsocitys (socity );
return userRepository.save(user);
}
I want to add a socity to an existing user
i try this but it doesn't work
public static void main(String[] args) {
ApplicationContext ctx = SpringApplication.run (App.class, args);
SocityDao SDao = ctx.getBean(SocityDao .class);
UserRepository userRepository = ctx.getBean(UserRepository.class);
User u = userRepository.findOne("");
Socity s = new Socity("soc1");
SDao .addSocity(e);
u.getSocitys().add(e);
}
this is the rest service
#RequestMapping(value = "up/{id}", method = RequestMethod.POST ,produces =
"application/json")
public User addSocityToUser(#RequestBody Socity, #PathVariable String id)
{
return SocityDAO.addSocityToUser(e, id);
}

Answer 1

In the end of your code add userRepository.save(u) to persist your changes to the DB.
As long as it as an ID (because it is a persisted object) it will be updated. if it has no ID it will be saved as a new object in the DB.

Answer 2

Looks like you forget to save user, after you add new socity. Please check my updates
#Document
public class Socity {
private String id ;
private String name;
}
#Document
public class User {
private String id;
private String name;
#DBRef
private List<Socity> socitys = new ArrayList<>();
}
Then you don't need to use your addUser() method. When you want to add new user just use
userRepository.save(user);
You also need two repositories
public interface SocityRepository extends MongoRepository<Socity, String> {
}
and
public interface UserRepository extends MongoRepository<User, String> {
}
And what you need in the main method
public static void main(String[] args) {
ApplicationContext ctx = SpringApplication.run (App.class, args);
UserRepository userRepository = ctx.getBean(UserRepository.class);
SocityRepository socityRepository = ctx.getBean(SocityRepository.class);
User u = userRepository.findOne("");
Socity s = socityRepository.save(new Socity("soc1"));
u.getSocitys().add(s);
userRepository.save(u);
}

Answer 3

It is always better to Use the MongoTemplate to write an update Query and use Push function to add to a list.
#Autowired
private MongoTemplate mongoTemplate;
function(String id, Socity socity){
Query query = new Query(Criteria.where("id").is(id));
Update update = new Update();
update.push("Socitys", socity);
mongoTemplate.updateFirst(query, update, User.class);
}