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Java Spring with Hibernate Getting Started with CRUD in Spring + Hibernate Add Saving to DAO & Service

Harrison Cassedy
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Harrison Cassedy
Java Web Development Techdegree Graduate 12,031 Points

task 1 of 3. Currently trying to see where I went wrong with my implementation.

In the ContactDao and ContactService interfaces, add a save method method that has a void return type and accepts a Contact object as its only parameter. I added the save method but don't see where I went wrong. It could be an oversight or something very simple. either way please look over it and provide some feedback for this novice coder. Thank you to those that contribute in advance.

com/teamtreehouse/contactmgr/dao/ContactDao.java
package com.teamtreehouse.contactmgr.dao;

import com.teamtreehouse.contactmgr.model.Contact;

import java.util.List;

public interface ContactDao {
    List<Contact> findAll();
    Contact findById(Long id);
}
com/teamtreehouse/contactmgr/dao/ContactDaoImpl.java
package com.teamtreehouse.contactmgr.dao;

import com.teamtreehouse.contactmgr.model.Contact;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public class ContactDaoImpl implements ContactDao {
    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public List<Contact> findAll() {
        Session session = sessionFactory.openSession();
        List<Contact> contacts = session.createCriteria(Contact.class).list();
        session.close();
        return contacts;
    }

    @Override
    public Contact findById(Long id) {
        Session session = sessionFactory.openSession();
        Contact c = session.get(Contact.class, id);
        session.close();
        return c;
    }
    @Override 
    public void save(Contact contact) {
        contactDAO.save(contact);
}
com/teamtreehouse/contactmgr/service/ContactService.java
package com.teamtreehouse.contactmgr.service;

import com.teamtreehouse.contactmgr.model.Contact;

import java.util.List;

public interface ContactService {
    List<Contact> findAll();
    Contact findById(Long id);
}
com/teamtreehouse/contactmgr/service/ContactServiceImpl.java
package com.teamtreehouse.contactmgr.service;

import com.teamtreehouse.contactmgr.dao.ContactDao;
import com.teamtreehouse.contactmgr.model.Contact;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class ContactServiceImpl implements ContactService {
    @Autowired
    private ContactDao contactDao;

    @Override
    public List<Contact> findAll() {
        return contactDao.findAll();
    }

    @Override
    public Contact findById(Long id) {
        return contactDao.findById(id);
    }

    @Override 
    public void save(Contact contact) {
      contactDAO.save(contact);
}

1 Answer

Daniel Vargas
Daniel Vargas
29,184 Points

Hi Harrison,

You should just create those methods in the interfaces first (at least in the task one):

public interface ContactService {
    List<Contact> findAll();
    Contact findById(Long id);
    void save(Contact contact);
}
public interface ContactDao {
    List<Contact> findAll();
    Contact findById(Long id);
    void save(Contact contact);
}

In the tasks 2 and 3 they then ask you to implement those methods in the ContactServiceImpl and ContactDaoImpl clases

Daniel Vargas
Daniel Vargas
29,184 Points

And in tasks 2 and 3 be careful with this:

 @Override 
    public void save(Contact contact) {
      contactDAO.save(contact);
}
  • You shouldn't capitalize all the letters in DAO it should be just: contactDao.save(contact)
  • If you are implementing that method in the ContactDaoImpl you can't call the contactDao.save(contact) method, because you are just defined it (it would be an infite loop). You should implement the save method opening a session, saving the contact and the closing the session (there are more steps between opening and closing the session but I don't want to give the answer away).

I hope I was clear enough, if you have any trouble let me know.