CDI模糊依存关系

问题描述：

我有一个 @SessionScoped @Named bean和一个用于用户对象的 @Producer 方法：

I have a @SessionScoped @Named bean with a @Producer method for a user object:

@Named @SessionScoped
public class UserBean implements Serializable
{
  //...
  @Named @Produces @LoggedIn @SessionScoped
  public MyUser getCurrentUser() {return user;}
}

这在我的设置（JBoss-7.1.1-Final）中正常工作，并且可以使用＃{currentUser.name} 从JSF页面访问用户字段。 code>。限定符为 org.jboss.seam.security.annotations.LoggedIn 。现在，我想在另一个 @Named Bean中的字段中， @Inject 该用户：

This works fine in my setup (JBoss-7.1.1-Final) and it's no problem to access the user fields from JSF pages with #{currentUser.name}. The qualifier is org.jboss.seam.security.annotations.LoggedIn. Now I want to @Inject this user in a field in another @Named Bean:

@Named
public class FavBean implements Serializable
{   
  private @Inject @LoggedIn MyUser currentUser;
}

这给了我错误：

org.jboss.weld.exceptions.DeploymentException:
WELD-001409 Ambiguous dependencies for type [MyUser] with qualifiers [@Default] at
  injection point [[field] @Inject @LoggedIn test.FavBean.currentUser].
Possible dependencies [[Managed Bean [class test.ejb.MyUser] with qualifiers
  [@Any @Default],
Producer Method [MyUser] with qualifiers [@Any @Default] declared as [[method]
  @Named @Produces @LoggedIn @SessionScoped public test.UserBean.getCurrentUser()]]]

我不了解第一个依赖项 Managed Bean [类test.ejb.MyUser] 此类是简单的 @Entity 并部署在EAR的ebb.jar中。作为一种解决方法，我目前正在注入 UserBean 从那里获取用户。

I don't understand the first dependency Managed Bean [class test.ejb.MyUser] This class is a simple @Entity and deployed in an ebb.jar in a EAR. As a workaround I'm currently injecting the UserBean get the user from there.

答

这是因为CDI按类型搜索bean，并且您的实体和生产者方法返回相同的类型。这就是为什么它含糊不清的原因。

This is because CDI searches for beans by type and your entity and the producer method return the same type. That's why it is ambiguous.

您需要定义一个新的限定词，并使用生产者方法对其进行注释。

You need to define a new qualifier and annotate it with your producer method.

@Qualifier
@Retention(RUNTIME)
@Target({METHOD, FIELD, PARAMETER, TYPE})
public @interface CurrentUser {
}

将此注释添加到您的生产者方法：

Add this annotation to your producer method:

@Named @Produces @CurrentUser @LoggedIn @SessionScoped
public MyUser getCurrentUser() {return user;}

CDI模糊依存关系

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