什么使一个bean是一个CDI bean？ [英] What makes a bean a CDI bean?

问题描述

在这个问题的最高答案中，例如： Java EE 6 @ javax.annotation.ManagedBean vs. @ javax.inject.Named vs. @ javax.faces.ManagedBean 我读到：

In the top answer to this question for example : Java EE 6 @javax.annotation.ManagedBean vs. @javax.inject.Named vs. @javax.faces.ManagedBean I read that:

要部署CDI bean，必须在类路径上的
META-INF文件夹中放置一个名为beans.xml的文件。一旦这样做，那么
中的每个bean都将成为一个CDI bean。

To deploy CDI beans, you must place a file called beans.xml in a META-INF folder on the classpath. Once you do this, then every bean in the package becomes a CDI bean.

还有人说：

如果要使用JSF页面中的CDI bean，可以使用javax.inject给它一个
名称。

If you want to use the CDI bean from a JSF page, you can give it a name using the javax.inject.Named annotation.

我有一个示例代码，如下所示：

I have a sample code that goes like this:

@ManagedBean
@ViewScoped
public class SignUpPage {

    private User user;

    @PostConstruct
    public void init() {
        user = new User();
    }

    @Inject
    private UserDao userDao;
// rest of the class

据我所知，我的bean仍然是一个JSF托管Bean，它不是一个CDI bean（或者是吗？）。顺便说一下，我的WEB-INF文件夹中有一个beans.xml。

So as far as I understand, my bean is still a JSF Managed Bean, it is not a CDI bean(or is it?). By the way, I have a beans.xml in my WEB-INF folder.

而@Inject在这里工作很好。此外，我可以使用EL访问bean（这让我认为它仍然是一个JSF Managed Bean）

And @Inject works just fine in here. Also, I can access the bean with EL just fine(which makes me think it is still a JSF Managed Bean)

UserDao类看起来像这样：

The UserDao class looks something like this:

@Stateless
public class UserDao {
    EntityManager em;
    @PostConstruct
    public void initialize(){
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("Persistence");
        em = emf.createEntityManager();
    }

所以，这是我知道的一个EJB ..

So, it is as far as I know an EJB..

这个例子中是否有任何CDI bean？ @Inject如何在这里工作？

So do I have any CDI beans in this example? How does @Inject work here?

希望我的问题很清楚，请问！

Hope my question is clear, Regards!

推荐答案

规范，每个JavaBean都是一个托管Bean （不要混淆JSF @ManagedBean ，这是一个不同的）在项目中，$ code> beans .xml 存在。所以每个类也有资格进行依赖注入。请注意，此类的默认范围是从属。

By CDI specification, every JavaBean is a Managed Bean (do not confuse it with JSF @ManagedBean, this is a different one) in project where the beans.xml is present. So every class is also eligible for dependency injection. Note that default scope of this class is Dependent.

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