blocks|key|671797|text|JPA旨在取代EJB2实体been，并已作为EJB3规范的一部分启动。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|671798|由于在EJB容器之外也使用JPA是有意义的，因此它现在有了自己的规范，但它仍然与EJB3相关，因为兼容的EJB3容器必须提供集成到容器的事务处理中的JPA实现。|671799|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

JPA has been designed to replace EJB2 entity beans, and has started as a part of the EJB3 specification. 

Since it makes sense to also use JPA outside of an EJB container, it has now its own specification, but it's still related to EJB3, since a compliant EJB3 container has to provide a JPA implementation, which integrates into the transaction handling of the container.

blocks|key|457637|text|你是正确的。JPA不仅要支持EJB，还要做更多的事情。这就是JPA成为单独的JSR或规范的原因。EJB在其规范中使用或启用了JPA，原因很简单，因为JPA是一个很好的标准。如果设计得当，您现在可以在不同的JPA供应商之间切换，而无需更改代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|457638|EJB规范可以独立于JPA使用(尽管JPA已经包含在EJB规范中)，同样，JPA还可以用于EJB规范之外的更多东西。然而，EJB规范允许将JPA实体管理器(及其用法)非常容易地注入到它的bean中，这使得编程变得更容易。当然，现在可以在CDI上使用新的JSR轻松实现:-)。|457639|所有支持EJB规范的应用服务器也应该支持JPA。您可以查看this+thread了解更多信息。|offset|length|457640|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/7945859/boundary-between-ejb-3-0-and-jpa^0|0|0|T|B|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@$F|S|G|T|1|U]]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

You are right. JPA has more to do than only supporting EJB. Thats the reason why JPA became a separate JSR or specification. EJB uses or enables the usage of JPA in its specification, simply because JPA is a good standard. You can now switch between JPA vendors without changing your code if designed properly. 

EJB specification can be used independent of JPA (although JPA has been included as a part of EJB spec) and likewise JPA can be used for many more stuff outside the EJB spec. Nevertheless, EJB specification enables the injection of JPA Entitiy Manager (and its usage) into its beans very easily which makes programming easier. Ofcourse this can now be achieved easily using a new JSR on CDI :-).

All the application server that supports EJB spec, should support JPA also. You can see <a href="https://stackoverflow.com/questions/7945859/boundary-between-ejb-3-0-and-jpa">this thread</a> for more information.

blocks|key|671974|text|在EJB规范2.1版之前，实体bean类必须实现javax.ejb.EntityBean接口，并为ejbLoad、ejbStore、ejbActivate和ejbPassivate等样板方法提供实现。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|671975|EJB3.0采用了JPA规范。实体bean的概念被更简单的JPA实体概念所取代。要创建这样的实体，不需要接口实现或样板方法。该实体是一个具有@Entity注释的POJO。|671976|因此，从EJB3开始，“实体bean”EJB在Java应用程序中的使用就消失了(埋藏在JPA之下)。|671977|entityMap^0|O|K|0|1Y|7|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|R|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|K|$]]

Up until version 2.1 of the EJB specifications, an entity bean class had to implement the <code>javax.ejb.EntityBean</code> interface and provide an implementation for boilerplate methods such as ejbLoad, ejbStore, ejbActivate, and ejbPassivate. 

EJB 3.0 adopted the JPA specification. The very notion of an entity bean was superceded by the simpler notion of a JPA entity. To create such entity, no interface implementation or boiler plate methods are required. The entity is a POJO that has the <code>@Entity</code> annotation. 

Thus, in practice the use of "entity bean" EJBs in Java EE applications is dead (buried under JPA) as of EJB 3.

I am reading the EJB 3 in Action book and I have the following question : 
Is the POJO's you write and annotate with @Entity and so on also a EJB entity type? 

I don't understand what JPA has to do with EJB. Isn't JPA a own specification now? The entities are also contained in a own persistence container. They talk about EJB 3 Java Persistence API etc. but I don't understand what entities has to do with EJB.

How does EJB and JPA relate?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在阅读EJB3 in Action一书，我有以下问题：您使用@Entity等编写和注释的POJO也是EJB实体类型吗？我不明白JPA和EJB有什么关系。JPA现在不是自己的规范了吗？这些实体也包含在自己的持久性容器中。他们谈论EJB3、Java持久性API等，但我不理解实体与EJB有什么关系。

问EJB和JPA有什么关系？
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