WELD-001408注入EntityManager时不满意的依赖关系

Question

我有@Statelessbean实现两个接口(远程和本地).我还添加@LocalBean了用于通过无接口视图访问bean的anotation.

@Stateless
@LocalBean
public class WeatherDataBean implements WeatherDataBeanRemote, WeatherDataBeanLocal {
    @Inject
    private EntityManager entityManager;

    public WeatherDataBean () {

    }
    // ....attributes, getter & setter methods ....
}

我使用@Inject这个原因取自JBoss AS7快速启动的这个例子:

我们使用来自CDI的"资源生成器"模式,将实体管理器的旧式@PersistenceContext注入"别名"为CDI样式注入.这允许我们在整个应用程序中使用一致的注入样式(@Inject).

以前我用过:

@PersistenceContext(unitName="WeatherStationJPA")
private EntityManager entityManager;

在EJB中,它没有任何问题.但是使用@Inject注释我得到这个错误:

WELD-001408在注入点[[field] @Inject private ejb.WeatherDataBean.entityManager]中带有限定符[@Default]的[EntityManager]类型的不满意依赖项

这是我如何定义类资源:

public class Resources {
     @SuppressWarnings("unused")
     @PersistenceContext(unitName="WeatherStationJPA")
     @Produces
     private EntityManager entityManager;

     @Produces
     FacesContext getFacesContext() {
         return FacesContext.getCurrentInstance();
     }
}

如果我尝试注入实体管理器,为什么会出现此错误？

编辑: 根据@LightGuard的请求,我正在添加我用来引用注释的包:

1. WeatherDataBean有:

   import javax.ejb.LocalBean;
   import javax.ejb.Stateless;
   import javax.inject.Inject;
   

2. 资源有:

   import javax.enterprise.inject.Produces;
   import javax.faces.context.FacesContext;
   import javax.inject.Singleton;
   import javax.persistence.EntityManager;
   import javax.persistence.PersistenceContext;
   

Answer 1

我遇到了类似的错误,原来我没有把一个beans.xml文件放在WEB-INF文件夹中.beans.xml文件可以是位于WEB-INF文件夹中的空文件.JBossAS检查该文件以启动CDI服务.

Answer 2

我只是遇到了同样的问题,我通过将这个类添加到我的项目中来解决这个问题

import java.util.logging.Logger;

import javax.enterprise.context.RequestScoped;
import javax.enterprise.inject.Produces;
import javax.enterprise.inject.spi.InjectionPoint;
import javax.faces.context.FacesContext;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

/**
 * This class uses CDI to alias Java EE resources, such as the persistence context, to CDI beans
 * 
 * <p>
 * Example injection on a managed bean field:
 * </p>
 * 
 * <pre>
 * &#064;Inject
 * private EntityManager em;
 * </pre>
 */
public class Resources {
   // use @SuppressWarnings to tell IDE to ignore warnings about field not being referenced directly
   @SuppressWarnings("unused")
   @Produces
   @PersistenceContext
   private EntityManager em;

  // @Produces
  // public Logger produceLog(InjectionPoint injectionPoint) {
   //   return Logger.getLogger(injectionPoint.getMember().getDeclaringClass().getName());
  // }

   @Produces
   @RequestScoped
   public FacesContext produceFacesContext() {
      return FacesContext.getCurrentInstance();
   }

}