使用weblogic 10g bean注入的空指針異常jpa/ejb

我的EJB/JPA項目存在問題。我使用netbeans，weblogic 10g和Java EE應用程序。使用weblogic 10g bean注入的空指針異常jpa/ejb

我的問題是，我創建了「從數據庫中的實體類」，之後，我創建了「實體類的會話bean」，這基本上是我的外觀。

然後我翻閱我的戰爭計劃並說「JSF實體類的頁面」Netbeans很好地創建了所有的類。

開始的時候我說我必須有一個持久化提供者，爲了這個目的我添加了「Hibernate JPA」庫。

這裏是我的ArchJpaController：

package JPAControllerS; 

import JPAControllerS.exceptions.NonexistentEntityException; 
import JPAControllerS.exceptions.RollbackFailureException; 
import entities.Arch; 
import java.io.Serializable; 
import java.util.List; 
import javax.persistence.EntityManager; 
import javax.persistence.EntityManagerFactory; 
import javax.persistence.EntityNotFoundException; 
import javax.persistence.Query; 
import javax.transaction.UserTransaction; 



public class ArchJpaController implements Serializable { 

    public ArchJpaController(UserTransaction utx, EntityManagerFactory emf) { 
     this.utx = utx; 
     this.emf = emf; 
    } 
    private UserTransaction utx = null; 
    private EntityManagerFactory emf; 

    public EntityManager getEntityManager() { 
     return emf.createEntityManager(); 
    } 

    public void create(Arch arch) throws RollbackFailureException, Exception { 
     EntityManager em = null; 
     try { 
      utx.begin(); 
      em = getEntityManager(); 
      em.persist(arch); 
      utx.commit(); 
     } catch (Exception ex) { 
      try { 
       utx.rollback(); 
      } catch (Exception re) { 
       throw new RollbackFailureException("An error occurred attempting to roll back the transaction.", re); 
      } 
      throw ex; 
     } finally { 
      if (em != null) { 
       em.close(); 
      } 
     } 
    } 

    public void edit(Arch arch) throws NonexistentEntityException, RollbackFailureException, Exception { 
     EntityManager em = null; 
     try { 
      utx.begin(); 
      em = getEntityManager(); 
      arch = em.merge(arch); 
      utx.commit(); 
     } catch (Exception ex) { 
      try { 
       utx.rollback(); 
      } catch (Exception re) { 
       throw new RollbackFailureException("An error occurred attempting to roll back the transaction.", re); 
      } 
      String msg = ex.getLocalizedMessage(); 
      if (msg == null || msg.length() == 0) { 
       Integer id = arch.getId(); 
       if (findArch(id) == null) { 
        throw new NonexistentEntityException("The arch with id " + id + " no longer exists."); 
       } 
      } 
      throw ex; 
     } finally { 
      if (em != null) { 
       em.close(); 
      } 
     } 
    } 

    public void destroy(Integer id) throws NonexistentEntityException, RollbackFailureException, Exception { 
     EntityManager em = null; 
     try { 
      utx.begin(); 
      em = getEntityManager(); 
      Arch arch; 
      try { 
       arch = em.getReference(Arch.class, id); 
       arch.getId(); 
      } catch (EntityNotFoundException enfe) { 
       throw new NonexistentEntityException("The arch with id " + id + " no longer exists.", enfe); 
      } 
      em.remove(arch); 
      utx.commit(); 
     } catch (Exception ex) { 
      try { 
       utx.rollback(); 
      } catch (Exception re) { 
       throw new RollbackFailureException("An error occurred attempting to roll back the transaction.", re); 
      } 
      throw ex; 
     } finally { 
      if (em != null) { 
       em.close(); 
      } 
     } 
    } 

    public List<Arch> findArchEntities() { 
     return findArchEntities(true, -1, -1); 
    } 

    public List<Arch> findArchEntities(int maxResults, int firstResult) { 
     return findArchEntities(false, maxResults, firstResult); 
    } 

    private List<Arch> findArchEntities(boolean all, int maxResults, int firstResult) { 
     EntityManager em = getEntityManager(); 
     try { 
      Query q = em.createQuery("select object(o) from Arch as o"); 
      if (!all) { 
       q.setMaxResults(maxResults); 
       q.setFirstResult(firstResult); 
      } 
      return q.getResultList(); 
     } finally { 
      em.close(); 
     } 
    } 

    public Arch findArch(Integer id) { 
     EntityManager em = getEntityManager(); 
     try { 
      return em.find(Arch.class, id); 
     } finally { 
      em.close(); 
     } 
    } 

    public int getArchCount() { 
     EntityManager em = getEntityManager(); 
     try { 
      Query q = em.createQuery("select count(o) from Arch as o"); 
      return ((Long) q.getSingleResult()).intValue(); 
     } finally { 
      em.close(); 
     } 
    } 
}

這裏是我的ArchController：

package JSFClasses; 

import entities.Arch; 
import JSFClasses.util.JsfUtil; 
import JSFClasses.util.PaginationHelper; 
import JPAControllerS.ArchJpaController; 

import java.io.Serializable; 
import java.util.ResourceBundle; 
import javax.annotation.Resource; 
import javax.faces.bean.ManagedBean; 
import javax.faces.bean.SessionScoped; 
import javax.faces.component.UIComponent; 
import javax.faces.context.FacesContext; 
import javax.faces.convert.Converter; 
import javax.faces.convert.FacesConverter; 
import javax.faces.model.DataModel; 
import javax.faces.model.ListDataModel; 
import javax.faces.model.SelectItem; 
import javax.persistence.EntityManagerFactory; 
import javax.persistence.PersistenceUnit; 
import javax.transaction.UserTransaction; 

@ManagedBean(name = "archController") 
@SessionScoped 
public class ArchController implements Serializable { 

    @Resource 
    private UserTransaction utx = null; 
    @PersistenceUnit(unitName = "IBB_Latest-warPU") 
    private EntityManagerFactory emf = null; 
    private Arch current; 
    private DataModel items = null; 
    private ArchJpaController jpaController = null; 
    private PaginationHelper pagination; 
    private int selectedItemIndex; 

    public ArchController() { 
    } 

    public Arch getSelected() { 
     if (current == null) { 
      current = new Arch(); 
      selectedItemIndex = -1; 
     } 
     return current; 
    } 

    private ArchJpaController getJpaController() { 
     if (jpaController == null) { 
      jpaController = new ArchJpaController(utx, emf); 
     } 
     return jpaController; 
    } 

    public PaginationHelper getPagination() { 
     if (pagination == null) { 
      pagination = new PaginationHelper(10) { 
       @Override 
       public int getItemsCount() { 
        return getJpaController().getArchCount(); 
       } 

       @Override 
       public DataModel createPageDataModel() { 
        return new ListDataModel(getJpaController().findArchEntities(getPageSize(), getPageFirstItem())); 
       } 
      }; 
     } 
     return pagination; 
    } 

    public String prepareList() { 
     recreateModel(); 
     return "List"; 
    } 

    public String prepareView() { 
     current = (Arch) getItems().getRowData(); 
     selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex(); 
     return "View"; 
    } 

    public String prepareCreate() { 
     current = new Arch(); 
     selectedItemIndex = -1; 
     return "Create"; 
    } 

    public String create() { 
     try { 
      getJpaController().create(current); 
      JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("ArchCreated")); 
      return prepareCreate(); 
     } catch (Exception e) { 
      JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured")); 
      return null; 
     } 
    } 

    public String prepareEdit() { 
     current = (Arch) getItems().getRowData(); 
     selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex(); 
     return "Edit"; 
    } 

    public String update() { 
     try { 
      getJpaController().edit(current); 
      JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("ArchUpdated")); 
      return "View"; 
     } catch (Exception e) { 
      JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured")); 
      return null; 
     } 
    } 

    public String destroy() { 
     current = (Arch) getItems().getRowData(); 
     selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex(); 
     performDestroy(); 
     recreatePagination(); 
     recreateModel(); 
     return "List"; 
    } 

    public String destroyAndView() { 
     performDestroy(); 
     recreateModel(); 
     updateCurrentItem(); 
     if (selectedItemIndex >= 0) { 
      return "View"; 
     } else { 
      // all items were removed - go back to list 
      recreateModel(); 
      return "List"; 
     } 
    } 

    private void performDestroy() { 
     try { 
      getJpaController().destroy(current.getId()); 
      JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("ArchDeleted")); 
     } catch (Exception e) { 
      JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured")); 
     } 
    } 

    private void updateCurrentItem() { 
     int count = getJpaController().getArchCount(); 
     if (selectedItemIndex >= count) { 
      // selected index cannot be bigger than number of items: 
      selectedItemIndex = count - 1; 
      // go to previous page if last page disappeared: 
      if (pagination.getPageFirstItem() >= count) { 
       pagination.previousPage(); 
      } 
     } 
     if (selectedItemIndex >= 0) { 
      current = getJpaController().findArchEntities(1, selectedItemIndex).get(0); 
     } 
    } 

    public DataModel getItems() { 
     if (items == null) { 
      items = getPagination().createPageDataModel(); 
     } 
     return items; 
    } 

    private void recreateModel() { 
     items = null; 
    } 

    private void recreatePagination() { 
     pagination = null; 
    } 

    public String next() { 
     getPagination().nextPage(); 
     recreateModel(); 
     return "List"; 
    } 

    public String previous() { 
     getPagination().previousPage(); 
     recreateModel(); 
     return "List"; 
    } 

    public SelectItem[] getItemsAvailableSelectMany() { 
     return JsfUtil.getSelectItems(getJpaController().findArchEntities(), false); 
    } 

    public SelectItem[] getItemsAvailableSelectOne() { 
     return JsfUtil.getSelectItems(getJpaController().findArchEntities(), true); 
    } 

    @FacesConverter(forClass = Arch.class) 
    public static class ArchControllerConverter implements Converter { 

     public Object getAsObject(FacesContext facesContext, UIComponent component, String value) { 
      if (value == null || value.length() == 0) { 
       return null; 
      } 
      ArchController controller = (ArchController) facesContext.getApplication().getELResolver(). 
        getValue(facesContext.getELContext(), null, "archController"); 
      return controller.getJpaController().findArch(getKey(value)); 
     } 

     java.lang.Integer getKey(String value) { 
      java.lang.Integer key; 
      key = Integer.valueOf(value); 
      return key; 
     } 

     String getStringKey(java.lang.Integer value) { 
      StringBuffer sb = new StringBuffer(); 
      sb.append(value); 
      return sb.toString(); 
     } 

     public String getAsString(FacesContext facesContext, UIComponent component, Object object) { 
      if (object == null) { 
       return null; 
      } 
      if (object instanceof Arch) { 
       Arch o = (Arch) object; 
       return getStringKey(o.getId()); 
      } else { 
       throw new IllegalArgumentException("object " + object + " is of type " + object.getClass().getName() + "; expected type: " + Arch.class.getName()); 
      } 
     } 
    } 
}

最後我的例外：

java.lang.NullPointerException 
    at JPAControllerS.ArchJpaController.getEntityManager(ArchJpaController.java:43) 
    at JPAControllerS.ArchJpaController.findArchEntities(ArchJpaController.java:132) 
    at JPAControllerS.ArchJpaController.findArchEntities(ArchJpaController.java:128) 
    at JSFClasses.ArchController$1.createPageDataModel(ArchController.java:66) 
    at JSFClasses.ArchController.getItems(ArchController.java:166) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:261) 
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176) 
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203) 
    at com.sun.el.parser.AstValue.getValue(AstValue.java:118) 
    at com.sun.el.parser.AstEqual.getValue(AstEqual.java:41) 
    at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:192) 
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109) 
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194) 
    at javax.faces.component.UIComponentBase.isRendered(UIComponentBase.java:413) 
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1750) 
    at javax.faces.render.Renderer.encodeChildren(Renderer.java:168) 
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845) 
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1756) 
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759) 
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759) 
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:401) 
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:134) 
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121) 
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) 
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139) 
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:410) 
    at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) 
    at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292) 
    at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:27) 
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:43) 
    at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27) 
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:43) 
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3496) 
    at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) 
    at weblogic.security.service.SecurityManager.runAs(Unknown Source) 
    at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2180) 
    at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2086) 
    at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1406) 
    at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) 
    at weblogic.work.ExecuteThread.run(ExecuteThread.java:173)

如果有人可以幫助我在這個問題上我會不勝感激。

來源

2013-02-25 Ali Yucel Akgul

我猜，你只需要在'ArchController'類'emx'屬性的制定者（以注入）。如果這樣做，那麼你也需要一個'utx'的setter。順便說一下，你在這個代碼示例中根本沒有使用EJBs。 – 2013-02-25 16:34:36

第一：您使用的是哪個版本的JPA？ 1.0或2.0？如果您使用2.0，默認情況下，weblogic不支持它。但可以啓用作出以下改動：

定位（對於Linux或sh）文件commEnv.cmd。該文件位於WEBLOGIC_HOME/common/bin中。例如用於窗口：C：\ ORACLE \中間件\ wlserver_10.3 \共同\ BIN
添加以下行到文件

@rem JAR AGREGADOS PARA EL SOPORTE DE JPA2.0 EN WLS 集PRE_CLASSPATH =％MW_HOME％/模塊/ javax.persistence_1.0.0.0_2-0-0.jar;％MW_HOME％/模塊/ com.oracle.jpa2support_1.0.0.0_2-0.jar
重啓德的WebLogic服務器

對於注射persitent單位，你可以使用

@PersistenceContext(unitName = "PersistenceUnitName") 
private EntityManager em;

在你的門面或DAO clasess

你並不需要一個EntityManagerFactory的注入。

我希望這對你有所幫助。

對不起，我的英語......它`真的不好.. :-(

來源

2013-02-25 16:55:12 Mario

非常感謝你的答案，但它也不能工作。 – 2013-02-25 20:15:02

使用weblogic 10g bean注入的空指針異常jpa/ejb

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