Jaxb:如何生成 ObjectFactory 类?

2022-01-19 00:00:00 java jaxb jaxb2

我正在使用 Java 6、JaxB 2 和 SpringSource Tool Suite(与 Eclipse 相同).我编写了几个 Java 类，我使用 JaxB 从中生成 XML 模式.但是，我注意到为了使用 JaxB 从 Java 对象生成 XML 文档的能力，我需要一个 ObjectFactory.

I'm using Java 6, JaxB 2 and SpringSource Tool Suite (same as Eclipse). I had a couple of Java classes I wrote, from which I used JaxB to generate an XML schema. However, I'm noticing in order to use JaxB's ability to generate an XML document from Java objects, I need an ObjectFactory. 

final Marshaller marshaller = jaxbContext.createMarshaller();
// Here is where I don't have an ObjectFactory defined
final JAXBElement<WebLeads> webLeadsElement  
         = (new ObjectFactory()).createWebLeads(webLeadsJavaObj);

如何在不破坏我现在已有的类的情况下生成 ObjectFactory?

How can I generate an ObjectFactory without blowing away the classes I already have now?

推荐答案

更新

这个问题可能是指ObjectFactory在创建JAXBContext中的作用.如果您在上下文路径上引导 JAXBContext，那么它将检查该位置中的 ObjectFactory 以确定该包中的类:

This question may be referring to the role of ObjectFactory in creating a JAXBContext. If you bootstrap a JAXBContext on a context path then it will check for an ObjectFactory in that location in order to determine the classes in that package:

  • http://bdoughan.blogspot.com/2010/09/processing-atom-feeds-with-jaxb.html

如果您没有 ObjectFactory 但仍希望在上下文路径上创建 JAXBContext 您可以包含一个名为 jaxb.in​​dex 在该包中列出要包含在 JAXBContext 中的文件(引用的类将自动拉入):

If you do not have an ObjectFactory but still wish to create you JAXBContext on a context path you can include a file called jaxb.index in that package listing files to be included in the JAXBContext (referenced classes will automatically pulled in):

  • http://bdoughan.blogspot.com/2010/08/using-xmlanyelement-to-build-generic.html

或者，您可以在类数组而不是上下文路径上引导您的 JAXBContext:

Alternatively you can bootstrap you JAXBContext on an array of classes instead of a context path:

  • http://bdoughan.blogspot.com/2010/11/jaxb-and-inheritance-using-xsitype.html

是否需要 ObjectFactory

ObjectFactory 不是必需的，尽管即使从 Java 类开始，也有一些用例可以利用带有 @XmlRegistry 以便使用 @XmlElementDecl 注释.

An ObjectFactory is not required, although even when starting from Java classes there are use cases where you can leverage a similar class annotated with @XmlRegistry in order to use the @XmlElementDecl annotation.

创建 JAXBElement 的实例

您始终可以直接创建 JAXBElement:

You can always create the JAXBElement directly:

final JAXBElement<WebLeads> webLeadsElement = new JAXBElement<WebLeads>(
    new QName("root-element-name"), 
    WebLeads.class, 
    webLeadsJavaObj);

JAXBElement 的替代品

或者由于 JAXBElement 仅用于提供根元素信息，您可以使用 @XmlRootElement 注释您的 WebLeads 类:

Or since JAXBElement is simply used to provide root element information, you can annotate your WebLeads class with @XmlRootElement:

@XmlRootElement(name="root-element-name")
public class WebLeads {
   ...
}

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