如何在@FacesValidator中注入@EJB，@PersistenceContext，@Inject，@Autowired [英] How to inject in @FacesValidator with @EJB, @PersistenceContext, @Inject, @Autowired
问题描述
如何注入一个依赖关系，如 @EJB ， @PersistenceContext ， @Inject ， @AutoWired 等在 @FacesValidator 中？在我的具体情况下，我需要通过 @AutoWired 注入一个Spring管理的bean：
How can I inject a dependency like @EJB, @PersistenceContext, @Inject, @AutoWired, etc in a @FacesValidator? In my specific case I need to inject a Spring managed bean via @AutoWired:
@FacesValidator("emailExistValidator")
public class EmailExistValidator implements Validator {
@Autowired
private UserDao userDao;
// ...
}
然而，它没有被注入，它仍然是 null ，导致 java.lang.NullPointerException 。
似乎 @EJB ， @PersistenceContext 和 @Inject 也不起作用。
However, it didn't get injected and it remains null, resulting in java.lang.NullPointerException.
It seems that @EJB, @PersistenceContext and @Inject also doesn't work.
如何在验证器中注入服务依赖关系，以便我可以访问数据库？
How do I inject a service dependency in my validator so that I can access the DB?
推荐答案
@FacesValidator 不受注射容器管理。您需要使其成为托管bean。使用Spring的 @Component ，CDI的 @Named 或JSF的 @ManagedBean ，而不是 @FacesValidator ，以使其成为受管理的bean，从而符合依赖注入资格。
The @FacesValidator isn't managed by the injection container. You need to make it a managed bean. Use Spring's @Component, CDI's @Named or JSF's @ManagedBean instead of @FacesValidator in order to make it a managed bean and thus eligible for dependency injection.
例如，假设你想使用JSF的 @ManagedBean ：
E.g., assuming that you want to use JSF's @ManagedBean:
@ManagedBean
@RequestScoped
public class EmailExistValidator implements Validator {
// ...
}
您还需要通过EL中的＃{name} 将其引用为托管bean，而不是作为验证器ID硬编码字符串。因此，所以
You also need to reference it as a managed bean by #{name} in EL instead of as a validator ID in hardcoded string. Thus, so
<h:inputText ... validator="#{emailExistValidator.validate}" />
或
<f:validator binding="#{emailExistValidator}" />
而不是
<h:inputText ... validator="emailExistValidator" />
或
<f:validator validatorId="emailExistValidator" />
这确实很尴尬。 JSF的人已经确认了这个令人尴尬的监督，他们将使 @FacesValidator （和 @FacesConverter ）合格的注射目标在即将到来的JSF 2.2 2.3中，另见 JSF规范问题763 。对于EJB，通过从JNDI手动抓取它可以解决这个问题，另见获取@EJB @FacesConverter和@FacesValidator 。如果您恰好使用CDI扩展程序 MyFaces CODI ，那么您也可以通过将
This is indeed awkward. The JSF guys have confirmed this embarrassing oversight and they will make the @FacesValidator (and @FacesConverter) an eligible injection target in upcoming JSF 2.2 2.3, see also JSF spec issue 763. For EJBs there's a workaround by manually grabbing it from JNDI, see also Getting an @EJB in @FacesConverter and @FacesValidator. If you happen to use the CDI extension MyFaces CODI, then you can also solve it by putting @Advanced annotation on the class.
- CDI Injection into a FacesConverter
- What's new in JSF 2.2 - Injection
更新：如果您碰巧使用JSF实用程序库 OmniFaces ，因为1.6版本为使用 @Inject 和 @EJB 添加了透明支持一个 @FacesValidator 类，没有任何其他配置或注释。另请参见 CDI @FacesValidator 展示示例。
Update: if you happen to use JSF utility library OmniFaces, since version 1.6 is adds transparent support for using @Inject and @EJB in a @FacesValidator class without any additional configuration or annotations. See also the CDI @FacesValidator showcase example.
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