是否可以@Inject一个@RequestScoped bean到@Stateless EJB？ [英] Is it possible to @Inject a @RequestScoped bean into a @Stateless EJB?

问题描述

是否可以将请求范围的CDI bean注入无状态会话bean？

Is it possible to inject a request-scoped CDI bean into a Stateless session bean?

我曾问过一个相关的问题，并认为具体的CDI @RequestScoped @Stateless问题值得自己发帖。

I had asked a related question and thought the specific CDI @RequestScoped into @Stateless question merited its own post.

传递EJB方法之间的状态/ @RequestScoped和@Stateless

我还问了一个关于JMS @MessageDriven bean的类似问题 - 基本上想知道关于@Stateless的相同问题。

I also asked a similar question about JMS @MessageDriven beans - basically want to know the same about @Stateless.

@RequestScoped CDI注入@MessageDriven bean

推荐答案

你绝对可以做你提到的并使用 @RequestScoped @Stateless 会话bean中的bean和 @MessageDriven bean。这是CDI规范和TCK的核心部分，保证便携。

You can absolutely do what you mention and use @RequestScoped beans in an @Stateless session bean and an @MessageDriven bean. This is a core part of the CDI spec and TCK and guaranteed portable.

是意识到对使用 @RequestScoped bean的 @Stateless bean进行了测试，但是没有测试保证 @MessageDriven bean可以引用 @RequestScoped bean。这只是一个疏忽，已经为Java EE 7 TCK修复了。所以请注意，如果它不适用于MDB案例，则可能不是您的错：:)

Do be aware that there is a test for a @Stateless bean that uses a @RequestScoped bean, but there is no test that guarantees a @MessageDriven bean can reference @RequestScoped beans. This was just an oversight and is already fixed for the Java EE 7 TCK. So just be aware that if it doesn't work for the MDB case, it may not be your fault :)

解决方法是简单地让您的MDB委托给一个任何类型的SessionBean，如 @Stateless ， @Stateful ，以及 @Singleton 所有人都有 @RequestScoped 测试。

The workaround would be to simply have your MDB delegate to a SessionBean of any kind as @Stateless, @Stateful, and @Singleton all have @RequestScoped tests.

当 @Stateless ， @Singleton 和 @ MessageDriven 可以通过 @Inject 注入范围内的引用，它们不能 @RequestScoped 或任何其他范围。只有 @Stateful 模型足够灵活，可以支持范围。换句话说，您可以将 @Stateful bean类本身注释为 @RequestScoped ， @ SessionScoped 等等。

While @Stateless, @Singleton and @MessageDriven can have scoped references injected via @Inject, they cannot be @RequestScoped or any other scope. Only the @Stateful model is flexible enough to support scopes. In other words, you can annotate the @Stateful bean class itself as @RequestScoped, @SessionScoped, etc..

简单来说 @Stateless ， @Singleton 已经修复了范围。 @Singleton 基本上是 @ApplicationScoped 和 @Stateless 也许是一些像 @InvocationScoped 这样的组成范围，如果存在的话。 @MessageDriven bean的生命周期完全取决于驱动它的连接器，因此也不允许具有用户定义的范围。

In simple terms @Stateless, @Singleton have fixed "scopes" already. @Singleton is essentially @ApplicationScoped and @Stateless would perhaps be some made-up scope like @InvocationScoped, if that existed. The lifecycle of an @MessageDriven bean is entirely up to the Connector that drives it and is therefore also not allowed to have user-defined scope.

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