Spring Boot - Bean named entityManagerFactory - postgresql

Question

I am trying to make a simple Spring Boot application generated with jHipster to get from a postgresql a list of articles from a postreSQL database and display it using a rest controller, but when i run it i get
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APPLICATION FAILED TO START
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Description:
Parameter 0 of constructor in org.adi.security.DomainUserDetailsService required a bean named 'entityManagerFactory' that could not be found.
Action:
Consider defining a bean named 'entityManagerFactory' in your configuration.
But the thing is that that `DomainUserDetailsService is something generated by jhipster which stopped working after i added my classes. So i will write below my classes:
Article Entity:
package org.adi.domain;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
#Entity
#Table(name="articles")
public class Article implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name="article_id")
private int articleId;
#Column(name="title")
private String title;
#Column(name="category")
private String category;
public int getArticleId() {
return articleId;
}
public void setArticleId(int articleId) {
this.articleId = articleId;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getCategory() {
return category;
}
public void setCategory(String category) {
this.category = category;
}
}
ArticleDAO (Repository):
#Transactional
#Repository
public class ArticleDAO implements IArticleDAO {
#PersistenceContext
private EntityManager entityManager;
#Override
public Article getArticleById(int articleId) {
return entityManager.find(Article.class, articleId);
}
#SuppressWarnings("unchecked")
#Override
public List<Article> getAllArticles() {
String hql = "FROM Article as atcl ORDER BY atcl.articleId DESC";
return (List<Article>) entityManager.createQuery(hql).getResultList();
}
#Override
public void createArticle(Article article) {
entityManager.persist(article);
}
#Override
public void updateArticle(Article article) {
Article artcl = getArticleById(article.getArticleId());
artcl.setTitle(article.getTitle());
artcl.setCategory(article.getCategory());
entityManager.flush();
}
#Override
public void deleteArticle(int articleId) {
entityManager.remove(getArticleById(articleId));
}
#Override
public boolean articleExists(String title, String category) {
String hql = "FROM Article as atcl WHERE atcl.title = ? and atcl.category = ?";
int count = entityManager.createQuery(hql).setParameter(1, title)
.setParameter(2, category).getResultList().size();
return count > 0 ? true : false;
}
}
ArticleService:
#Service
public class ArticleService implements IArticleService {
#Autowired
private IArticleDAO articleDAO;
#Override
public Article getArticleById(int articleId) {
Article obj = articleDAO.getArticleById(articleId);
return obj;
}
#Override
public List<Article> getAllArticles(){
return articleDAO.getAllArticles();
}
#Override
public synchronized boolean createArticle(Article article){
if (articleDAO.articleExists(article.getTitle(), article.getCategory())) {
return false;
} else {
articleDAO.createArticle(article);
return true;
}
}
#Override
public void updateArticle(Article article) {
articleDAO.updateArticle(article);
}
#Override
public void deleteArticle(int articleId) {
articleDAO.deleteArticle(articleId);
}
}
and finally my REST controller:
#Controller
#RequestMapping("user")
#CrossOrigin(origins = {"http://localhost:4200"})
public class ArticleController {
#Autowired
private IArticleService articleService;
#GetMapping("article")
public ResponseEntity<Article> getArticleById(#RequestParam("id") String id) {
Article article = articleService.getArticleById(Integer.parseInt(id));
return new ResponseEntity<Article>(article, HttpStatus.OK);
}
#GetMapping("all-articles")
public ResponseEntity<List<Article>> getAllArticles() {
List<Article> list = articleService.getAllArticles();
return new ResponseEntity<List<Article>>(list, HttpStatus.OK);
}
#PostMapping("article")
public ResponseEntity<Void> createArticle(#RequestBody Article article, UriComponentsBuilder builder) {
boolean flag = articleService.createArticle(article);
if (flag == false) {
return new ResponseEntity<Void>(HttpStatus.CONFLICT);
}
HttpHeaders headers = new HttpHeaders();
headers.setLocation(builder.path("/article?id={id}").buildAndExpand(article.getArticleId()).toUri());
return new ResponseEntity<Void>(headers, HttpStatus.CREATED);
}
#PutMapping("article")
public ResponseEntity<Article> updateArticle(#RequestBody Article article) {
articleService.updateArticle(article);
return new ResponseEntity<Article>(article, HttpStatus.OK);
}
#DeleteMapping("article")
public ResponseEntity<Void> deleteArticle(#RequestParam("id") String id) {
articleService.deleteArticle(Integer.parseInt(id));
return new ResponseEntity<Void>(HttpStatus.NO_CONTENT);
}
}

Answer 1

Did you create a Persistence Unit?
[Reference]=> https://docs.oracle.com/cd/E19798-01/821-1841/bnbrj/index.html
Once you already have the persistence-unit's tag defined you are able to create your entity manager like this:
private final String PERSISTENCE_UNIT_NAME = "PUName";
private EntityManagerFactory eMFactory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
EntityManager entityManager=eMFactory.createEntityManager();