通过GWT-RPC发送持久化的JDO实例 [英] Sending persisted JDO instances over GWT-RPC

问题描述

我的想法是否正确：如果您想坚持一段时间业务对象（例如股票）使用JDO并将它发送到/来自客户端通过RPC，然后必须为该对象创建两个单独的类：一个JDO注释用于将它保存在服务器上，另一个可以通过RPC进行序列化和使用？

我注意到Stock Watcher有单独的类，我可以理论化为什么：

• 否则，gwt编译器会尝试
  为所有内容生成javascript
  引用的持久化类像
  JDO和com.google.blah.users.User等


• 在服务器端
  类中也可能有逻辑，它不适用于客户端
  ，反之亦然。

我只是想确保我正确理解这一点。如果我不需要 ，我不想创建我想用于RPC 的所有业务对象类的两个版本。

解决方案

简短回答是：您不需要创建重复的类。

我建议您从gwt-contributors列表的以下Google小组讨论中看一看：

http://groups.google.com/group/google-web-toolkit-contributors/browse_thread/thread/

以下是一段有趣的摘录：如果这是你感兴趣的全部内容，那么I
描述了一种使GAE和
GWT-RPC从
盒子中一起工作的方法。只需将您的实体声明为：
@PersistenceCapable（identityType =
IdentityType.APPLICATION，可分离
=false）public class MyPojo实现Serializable {}

，一切都会正常工作，但是当
从客户端发送回服务器时，
必须手动处理
重新连接。

您可以使用此选项，并且不需要镜像（DTO）类。
您也可以尝试 gilead （以前的hibernate4gwt），它会在序列化增强对象的过程中处理一些细节。

I've just started learning Google Web Toolkit and finished writing the Stock Watcher tutorial app.

Is my thinking correct that if one wants to persist a business object (like a Stock) using JDO and send it back and forth to/from the client over RPC then one has to create two separate classes for that object: One with the JDO annotations for persisting it on the server and another which is serialisable and used over RPC?

I notice the Stock Watcher has separate classes and I can theorise why:

• Otherwise the gwt compiler would try to generate javascript for everything the persisted class referenced like JDO and com.google.blah.users.User, etc
• Also there may be logic on the server-side class which doesn't apply to the client and vice-versa.

I just want to make sure I'm understanding this correctly. I don't want to have to create two versions of all my business object classes which I want to use over RPC if I don't have to.

解决方案

The short answer is: you don't need to create duplicate classes.

I recommend that you take a look from the following google groups discussion on the gwt-contributors list:

http://groups.google.com/group/google-web-toolkit-contributors/browse_thread/thread/3c768d8d33bfb1dc/5a38aa812c0ac52b

Here is an interesting excerpt:

If this is all you're interested in, I described a way to make GAE and GWT-RPC work together "out of the box". Just declare your entities as: @PersistenceCapable(identityType = IdentityType.APPLICATION, detachable = "false") public class MyPojo implements Serializable { }

and everything will work, but you'll have to manually deal with re-attachment when sending objects from the client back to the server.

You can use this option, and you will not need a mirror (DTO) class. You can also try gilead (former hibernate4gwt), which takes care of some details within the problems of serializing enhanced objects.

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