I have a OneToOne relation for my Course Entity.In course create page I want to select relation field (Teacher) from a drop down list (selectOneMenu). as I know for this kind of operation you have to implement the Converter interface.but there is problem in my implemented class. my EJB annotation dose not work. so i cannot retrieve the convert value from my database.
Teacher relation for showing the list of teacher in selectOneMenu.It works very well
@ManagedBean
@ApplicationScoped
public class TeacherRelation {
@EJB
private TeacherFacade teacherFacade;
public List<Teacher> getAllTeachers() {
List<Teacher> teacherList=new ArrayList<Teacher>();
teacherList=teacherFacade.findAll();
return teacherList;
}
}
the menu:
<h:selectOneMenu id="teacher" value="#{courseMB.course.teacher}" converter="teacherConvertor">
<f:selectItems value="#{teacherRelation.allTeachers}" id="items" var="teacherV" itemLabel="#{teacherV.lastName}" />
</h:selectOneMenu>
and finally important one.The implemented class
@RequestScoped
@ManagedBean
@FacesConverter("teacherConvertor")
public class TeacherConvertor implements Converter,Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
@EJB
private static TeacherFacade teacherFacade;
@Override
public Object getAsObject(FacesContext ctx, UIComponent component, String value) {
Long id=Long.valueOf(value);
return teacherFacade.find(id);
}
@Override
public String getAsString(FacesContext facesContext, UIComponent component, Object value) {
return ((Teacher)value).getId().toString();
}
}
Servlet.service() for servlet Faces Servlet threw exception: java.lang.NullPointerException is the Exception when teacherFacade.find is executing.actually teacherFacade is null.What i have to do?
