entitymanager

问题 I have recently created a web service that uses a static method in Java to obtain a list of items from the database. The web service works perfectly and returns JSON back to the caller. However, it works only once. If you try to refresh or make a new request, I get a EntityManagerFactory is closed error. Here's how the Web Service class looks like: public class WebService extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws

问题 I have recently created a web service that uses a static method in Java to obtain a list of items from the database. The web service works perfectly and returns JSON back to the caller. However, it works only once. If you try to refresh or make a new request, I get a EntityManagerFactory is closed error. Here's how the Web Service class looks like: public class WebService extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws

问题 I have recently created a web service that uses a static method in Java to obtain a list of items from the database. The web service works perfectly and returns JSON back to the caller. However, it works only once. If you try to refresh or make a new request, I get a EntityManagerFactory is closed error. Here's how the Web Service class looks like: public class WebService extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws

问题 I would like to use the autowiring in a service that use 2 different entity manager. How to achieve something like that ? use Doctrine\ORM\EntityManager; class TestService { public function __construct(EntityManager $emA, EntityManager $emB) { } } My service.yml file use to be configured like that : app.testservice: class: App\Services\TestService arguments: - "@doctrine.orm.default_entity_manager" - "@doctrine.orm.secondary_entity_manager" 回答1: Dylan's answer violates the Demeter's Law

问题 I have an EJB bean which have a method that call another method from the bean with parallel stream. It works fine, but in the async method I must update entity in the db and when I call entityManager.merge than I got a NullPointerExpcetion. I don't know why. I use OpenJPA on WebSphere. The original question was: Call a method for List in parallel? @Stateless public class TestBean implements LocalInterface, RemoterInterface { @PersistenceContext(unitName = Constants.PERSISTENCE_UNIT) protected

问题 The bounty expires in 6 days . Answers to this question are eligible for a +50 reputation bounty. Prashant Kumar wants to draw more attention to this question. I am working on replacing below sql query and use entitymanager criteriabuilder. I checked other blogs and documentation but haven't been successful yet. SELECT MIN(creation_date),MAX(creation_date),COUNT(*), source FROM creation_tbl where creation_date>=? GROUP BY source; My current approach CriteriaBuilder criteriaBuilder =

问题 I have three tables Employee, Boss, and Address. Employee and Boss in this case share the same Address. When I call EntityManager.remove on Employee I get an Integrity Constraint exception because it tries to delete the Address which it can't because Boss still needs it. If no one is using the Address though I would want it to be removed. What should my annotations look like so that I can delete orphans from Address but avoid the integrity constraint? Exception = Internal Exception: java.sql

问题 I'm new in Micronaut framework and I'm trying to use entitymanager to create my repository. I created my repository like this public interface EmployeeRepository { Employee save(@NotNull Employee employee); Employee update(@NotNull Employee employee); List<Employee> findAll(); Optional<Employee> findById(@NotNull Long id); } and I used this class to implement the interface and to inject entitymanager @Singleton public class EmployeeRepositoryImpl implements EmployeeRepository{

问题 Describe briefly the whole situation. I have an entity public class MovieEntity { ... @OneToMany(mappedBy = "movie", cascade = CascadeType.ALL) private Set<MovieOtherTitle> otherTitles; ... } I save a movie in the database using the JPA Spring Data repository this.movieRepository.save(movie); Then I add another title to the film final MovieOtherTitle movieOtherTitle = new MovieOtherTitle(otherTitle.getTitle(), otherTitle.getCountry()); movieOtherTitle.setMovie(movie); movieOtherTitle.setUser

问题 In my project, I forgot to close the entity manager for each operation. After some time, I got exception due to excessive connections to mysql server. Does this mean that each entity manager establish the connection? What will happen when we forget to close the connection? I have used only one entity manager factory. 回答1: Assuming that you are using an application-managed entity manager, then you are responsible for initializing and closing the entity manager. One the other hand, if you are