java EJB 3.1 依赖注入失败

EJB 3.1 Dependency Injection Failed

提问by nicholas

i have created a stateless session bean like this :

我创建了一个像这样的无状态会话 bean：

@WebServlet(name = "ProductController", urlPatterns = {"/ProductController"})
public class ProductController extends HttpServlet {

  @EJB
  private ProductFacadeBean productBean;
}

@Stateless
public class ProductFacadeBean extends AbstractFacade<Product> implements ProductFacadeLocalInterface {
  @PersistenceContext(unitName = "OnlineStorePU")
  private EntityManager em;

  protected EntityManager getEntityManager() {
    return em;
  }

  public ProductFacadeBean() {
    super(Product.class);
  }

}

@Local
public interface ProductFacadeLocalInterface {

  void create(Product product);

  void edit(Product product);

  void remove(Product product);

  Product find(Object id);

  List<Product> findAll();

  List<Product> findRange(int[] range);

  int count();

}


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();
  }

}

Question :

问题 ：

1. What is the error about ? How to solve it ?

   javax.naming.NamingException: Lookup failed for 'java:comp/env/Controller.ProductController/productBean' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NamingException: Exception resolving Ejb for 'Remote ejb-ref name=Controller.ProductController/productBean,Remote 3.x interface =EJB.ProductFacadeBean,ejb-link=null,lookup=,mappedName=,jndi-name=EJB.ProductFacadeBean,refType=Session' . Actual (possibly internal) Remote JNDI name used for lookup is 'EJB.ProductFacadeBean#EJB.ProductFacadeBean' [Root exception is javax.naming.NamingException: Lookup failed for 'EJB.ProductFacadeBean#EJB.ProductFacadeBean' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NameNotFoundException: EJB.ProductFacadeBean#EJB.ProductFacadeBean not found]]]

1. 错误是什么？如何解决？

   javax.naming.NamingException：在 SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java. Naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [根异常是 javax.naming.NamingException: 'Remote ejb-ref name=Controller.ProductController/productBean,Remote 3.x interface =EJB.ProductFacadeBean,ejb-link=null,lookup=,mappedName=,jndi-name=EJB.ProductFacadeBean,refType=Session 的异常解析 Ejb ' . 用于查找的实际（可能是内部的）远程 JNDI 名称是“EJB.ProductFacadeBean#EJB.ProductFacadeBean”[根异常是 javax.naming.NamingException:

The full exception is attached here :

完整的例外附在此处：

HTTP Status 500 -

type Exception report

message

descriptionThe server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: PWC1392: Error instantiating servlet class Controller.ProductController

root cause

com.sun.enterprise.container.common.spi.util.InjectionException: Error creating managed object for class Controller.ProductController

root cause

com.sun.enterprise.container.common.spi.util.InjectionException: Exception attempting to inject Remote ejb-ref name=Controller.ProductController/productBean,Remote
3.x interface =EJB.ProductFacadeBean,ejb-link=null,lookup=,mappedName=,jndi-name=EJB.ProductFacadeBean,refType=Session into class Controller.ProductController

root cause

javax.naming.NamingException: Lookup failed for 'java:comp/env/Controller.ProductController/productBean' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NamingException: Exception resolving Ejb for 'Remote ejb-ref name=Controller.ProductController/productBean,Remote
3.x interface =EJB.ProductFacadeBean,ejb-link=null,lookup=,mappedName=,jndi-name=EJB.ProductFacadeBean,refType=Session' .  Actual (possibly internal) Remote JNDI name used for lookup is 'EJB.ProductFacadeBean#EJB.ProductFacadeBean' [Root exception is javax.naming.NamingException: Lookup failed for 'EJB.ProductFacadeBean#EJB.ProductFacadeBean' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NameNotFoundException: EJB.ProductFacadeBean#EJB.ProductFacadeBean not found]]]

root cause

javax.naming.NamingException: Exception resolving Ejb for 'Remote ejb-ref name=Controller.ProductController/productBean,Remote
3.x interface =EJB.ProductFacadeBean,ejb-link=null,lookup=,mappedName=,jndi-name=EJB.ProductFacadeBean,refType=Session' .  Actual (possibly internal) Remote JNDI name used for lookup is 'EJB.ProductFacadeBean#EJB.ProductFacadeBean' [Root exception is javax.naming.NamingException: Lookup failed for 'EJB.ProductFacadeBean#EJB.ProductFacadeBean' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NameNotFoundException: EJB.ProductFacadeBean#EJB.ProductFacadeBean not found]]

root cause

javax.naming.NamingException: Lookup failed for 'EJB.ProductFacadeBean#EJB.ProductFacadeBean' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NameNotFoundException: EJB.ProductFacadeBean#EJB.ProductFacadeBean not found]

root cause

javax.naming.NameNotFoundException: EJB.ProductFacadeBean#EJB.ProductFacadeBean not found

note The full stack traces of the exception and its root causes are available in the GlassFish Server Open Source Edition 3.1 logs. GlassFish Server Open Source Edition 3.1

1. When i created the session for entity bean using netbeans it created the abstract facade for us ? What is the purpose ? I know facade pattern is to serve as interface to route the request ?
2. What is the use of ejb-jar.xml ?

1. 当我使用 netbeans 创建实体 bean 的会话时，它为我们创建了抽象外观？目的是什么 ？我知道外观模式是作为路由请求的接口吗？
2. ejb-jar.xml 有什么用？

All settings are default. The ejb bean is created inside java ee 6 web application rather than in another war or jar. Glassfish 3.1 server.

所有设置均为默认设置。ejb bean 是在 java ee 6 web 应用程序中创建的，而不是在另一个 war 或 jar 中创建的。Glassfish 3.1 服务器。

Please help.

请帮忙。

Thanks.

谢谢。

回答by aseychell

You need to inject the bean by refering to its interface and not to its implementation directly. Something like this ..

您需要通过引用它的接口而不是直接引用它的实现来注入 bean。像这样的东西..

@EJB
private ProductFacadeLocalInterface productBean;

You can then access the bean using the interface methods that you exposed in ProductFacadeLocalInterface.

然后，您可以使用在 中公开的接口方法访问 bean ProductFacadeLocalInterface。

回答by Cosmin Cosmin

you must use the interface. If you use Seam Solderand CDIyou can specify the exact implementation with

您必须使用该接口。如果您使用Seam Solder并且CDI您可以指定确切的实现

@Inject
@Exact(ProductFacadeBean.class)