Why don't you make a git repo (eg on github)?
This way, it's much easier for others to check upon your code and deploy it
locally.
just my 2 cents,
Regards,
Duncan
On Tue, Feb 7, 2012 at 4:35 PM, <forums_at_java.net> wrote:
> Hi guys,
>
> can someone with JPA experience PLEASE help me. All I want to do is
> persist
> an entity to a database. Sounds easy yes? I have been trying for two
> weeks solid now to persist a simple Persons class to a database with a
> table
> called persons with an id, firstName and age field. I have asked in many
> java forums but come up with the same answers, which don't help. I am
> trying to use a container injected EJB for the work. I am using netbeans
> (comes with glassfish 3.1.1). I can read from the database no problem but
> I
> keep getting a null pointer exception when I try to persist to it. I have
> a
> simple jsp page with a form that takes the users first name and age, when
> they hit submit I want to store it in a database.
>
> My servlets POST method which takes the users info and send the object to
> be
> persisted:
>
> protected void doPost(HttpServletRequest request, HttpServletResponse
> response)
> throws ServletException, IOException {
> String userPath = request.getServletPath();
>
> if(userPath.equals("/result"))**{
> String firstName = request.getParameter("**firstName");
> String age = request.getParameter("age");
>
> Persons p = new Persons();
> p.setFirstName(firstName);
> p.setAge(age);
> pf.create(p);
>
> }
> // use RequestDispatcher to forward request internally
> String url = "/WEB-INF/view" + userPath + ".jsp";
> try {
> request.getRequestDispatcher(**url).forward(request,
> response);
> } catch (Exception ex) {
> ex.printStackTrace();
> }
> }
>
>
>
> The PersonFacade class generated by netbeans "create session from entiy
> classes" wizard and its associated abstract facace:
>
> @Stateless
> public class PersonsFacade extends AbstractFacade<Persons> {
> @PersistenceContext(unitName = "FormTestPU")
> private EntityManager em;
> @Override
> protected EntityManager getEntityManager() {
> return em;
> }
> public PersonsFacade() {
> super(Persons.class);
> }
>
> }
>
>
> public abstract class AbstractFacade<T> {
> private Class<T> entityClass;
> public AbstractFacade(Class<T> entityClass) {
> this.entityClass = entityClass;
> }
> protected abstract EntityManager getEntityManager();
> public void create(T entity) {
> getEntityManager().persist(**entity);
> }
> public void edit(T entity) {
> getEntityManager().merge(**entity);
> }
> public void remove(T entity) {
> getEntityManager().remove(**getEntityManager().merge(**entity));
> }
> public T find(Object id) {
> return getEntityManager().find(**entityClass, id);
> }
> public List<T> findAll() {
> javax.persistence.criteria.**CriteriaQuery cq =
> getEntityManager().**getCriteriaBuilder().**createQuery();
> cq.select(cq.from(entityClass)**);
> return getEntityManager().**createQuery(cq).getResultList(**);
> }
> public List<T> findRange(int[] range) {
> javax.persistence.criteria.**CriteriaQuery cq =
> getEntityManager().**getCriteriaBuilder().**createQuery();
> cq.select(cq.from(entityClass)**);
> javax.persistence.Query q =
> getEntityManager().**createQuery(cq);
> q.setMaxResults(range[1] - range[0]);
> q.setFirstResult(range[0]);
> return q.getResultList();
> }
> public int count() {
> javax.persistence.criteria.**CriteriaQuery cq =
> getEntityManager().**getCriteriaBuilder().**createQuery();
> javax.persistence.criteria.**Root<T> rt = cq.from(entityClass);
> cq.select(getEntityManager().**getCriteriaBuilder().count(rt)**);
> javax.persistence.Query q =
> getEntityManager().**createQuery(cq);
> return ((Long) q.getSingleResult()).intValue(**);
> }
>
> }
>
> The entity class:
>
> @Entity
> @Table(name = "persons")
> @XmlRootElement
> @NamedQueries({
> @NamedQuery(name = "Persons.findAll", query = "SELECT p FROM Persons
> p"),
> @NamedQuery(name = "Persons.findById", query = "SELECT p FROM Persons
> p WHERE p.id = :id"),
> @NamedQuery(name = "Persons.findByAge", query = "SELECT p FROM Persons
> p WHERE p.age = :age"),
> @NamedQuery(name = "Persons.findByFirstName", query = "SELECT p FROM
> Persons p WHERE p.firstName = :firstName")})
> public class Persons implements Serializable {
> private static final long serialVersionUID = 1L;
> @Id
> @GeneratedValue(strategy = GenerationType.IDENTITY)
> @Basic(optional = false)
> @NotNull
> @Column(name = "Id")
> private Integer id;
> @Size(max = 255)
> @Column(name = "Age")
> private String age;
> @Size(max = 255)
> @Column(name = "FirstName")
> private String firstName;
> public Persons() {
> }
> public Persons(Integer id) {
> this.id = id;
> }
> public Integer getId() {
> return id;
> }
> public void setId(Integer id) {
> this.id = id;
> }
> public String getAge() {
> return age;
> }
> public void setAge(String age) {
> this.age = age;
> }
> public String getFirstName() {
> return firstName;
> }
> public void setFirstName(String firstName) {
> this.firstName = firstName;
> }
>
> }
>
> My persistence.xml file:
>
> <persistence version="2.0" xmlns="http://java.sun.com/**xml/ns/persistence<http://java.sun.com/xml/ns/persistence>
> "
> xmlns:xsi="http://www.w3.org/**2001/XMLSchema-instance<http://www.w3.org/2001/XMLSchema-instance>
> "
> xsi:schemaLocation="http://**java.sun.com/xml/ns/**persistence<http://java.sun.com/xml/ns/persistence>
> http://java.sun.com/xml/ns/**persistence/persistence_2_0.**xsd<http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd>
> ">
> <persistence-unit name="FormTestPU" transaction-type="JTA">
> <jta-data-source>jdbc/**formtest</jta-data-source>
> <class>entity.Persons</class>
> <properties/>
> </persistence-unit>
> </persistence>
>
>
> I know that the entity manager in the person facade class is not meant to
> be
> instantiated because it is injected by the container so I am at a loss to
> why
> I am getting a null pointer exception.
>
> Any help would be greatly appreciated!
>
> Thanks,
> Alan
>
>
> --
>
> [Message sent by forum member 'asmith2306']
>
> View Post: http://forums.java.net/node/**883335<http://forums.java.net/node/883335>
>
>
>