Converting DBObject to Java Object while retrieve values from MongoDB

Question

From my Java application, I have stored the values in mongoDB in ArrayList(set of Java objects). How can I retrieve the data from DBObject

I am storing the data in mong

Answer 1

You generally use an ORM tool for that (though it wouldn't be meaningful to call it ORM in the case of a non relational database).

There are several such tools. I like spring-data, which hides a lot of boiler plate code for you and gives you a simple, clean syntax. Something like this:

@Repository
public class UserRepositoryImpl implements UserRepository {

    private MongoTemplate mongoTemplate;

    @Autowired
    public UserRepositoryImpl(MongoTemplate mongoTemplate) {
        this.mongoTemplate = mongoTemplate;
    }

    @Override
    public User findsUserByUsernameAndPassword(String userName, String encodedPassword) {
        return mongoTemplate.findOne(query(where("userName").is(userName).and("encodedPassword").is(encodedPassword)), User.class);
    }
}

With the User class defined as:

@Document(collection = "users")
public class User {

    private String userName;

    private String encodedPassword;

    // snip getters and setters

}