JAXB xjc：简单绑定不会为基类生成@XmlRootElement [英] JAXB xjc:simple binding does not generate @XmlRootElement for base class

问题描述

我正在使用JAXB 2.0。我在XSD文件中定义了各种元素和类型。这是一个例子：

I am using JAXB 2.0. I have various elements and types defined in an XSD file. Here's an example:

<xs:element name="Person" type="Person" />
<xs:complexType name="Person">
    <xs:attribute name="name" type="xs:string"/>
</xs:complexType>

<xs:element name="Musician" type="Musician"/>
<xs:complexType name="Musician">
    <xs:complexContent>
        <xs:extension base="Person">
             <xs:attribute name="instrument" type="xs:string"/>
        </xs:extension>
    </xs:complexContent>
</xs:complexType>

<xs:element name="People" type="People"/>
<xs:complexType name="People">
    <xs:sequence>
        <xs:element name="person" type="Person" minOccurs="0" maxOccurs="Unbounded/>
    </xs:sequence>
</xs:complexType>

从上面的架构示例中可以看出，我们有一个Person，一个名字，一个音乐家，也是一个人（虽然这可能会受到一些争论，但那是另一个论坛）。还有一个People元素，它本质上是Person类型的集合。

So as you can see from the above schema example, we have a Person, who has a name, and a Musician, who is also a Person (though this may be subject to some debate, but that's for another forum). There is also a People element, which is essentially a collection of Person types.

我在绑定文件中有以下内容：

I have the following in a bindings file:

<?xml version="1.0" encoding="UTF-8"?>
<jaxb:bindings xmlns:jaxb="http://java.sun.com/xml/ns/jaxb" 
jaxb:version="2.0" 
xmlns:xjc= "http://java.sun.com/xml/ns/jaxb/xjc" 
jaxb:extensionBindingPrefixes="xjc"> 
    <jaxb:globalBindings optionalProperty="wrapper"> 
            <xjc:simple/>
    </jaxb:globalBindings> 

我的意图d使用这些对象是：

My intended use of these objects is:

1. 一个人可能看起来像一个单独的Marshalled元素，或者可能是People对象的一部分


2. 如果Person是People对象的一部分，那么xsi：type应该表明它只是普通人还是音乐家。

所以我需要生成的Java类包含@XmlRootElement注释和@XmlType注释。 xjc：simple绑定为音乐家创建两个注释，但只为Person创建@XmlType。因此，当我对一个Person对象进行Marshall时，我得到的只是：

So I need the generated Java classes to contain both an @XmlRootElement annotation as well as an @XmlType annotation. The xjc:simple binding creates both annotations for a Musician, but only creates the @XmlType for Person. So when I Marshall a Person object, all I get is:

<?xml version="1.0" encoding="UTF-8"?>

我希望看到的是：

<?xml version="1.0" encoding="UTF-8"?>
<Person name="John Doe"/>

对于People对象，我想看：

For a People object, I want to see:

<?xml version="1.0" encoding="UTF-8"?>
<People>
    <person name="John Doe" xsi:type="Person"/>
    <person name="Keith Richards" xsi:type="Musician"/>
</People>

我读过关于xjc的简单绑定，它适用于继承中的所有最低级别层次结构。但是，基类最终没有@XmlRootElement注释。对于我正在研究的用例，必须将基类作为顶级元素和其他元素的成员进行编组。任何建议都是受欢迎的。

I have read about the simple binding with xjc, and it works with all the lowest levels in an inheritance hierarchy. However, the base classes end up without an @XmlRootElement annotation. For the use case I'm working on, it's imperative that base classes can be Marshalled as both a top-level element and as a member of other elements. Any suggestions would be welcome.

推荐答案

https://github.com/highsource/jaxb2-annotate-plugin

<?xml version="1.0" encoding="UTF-8"?>
<jaxb:bindings xmlns:annox="http://annox.dev.java.net"
               xmlns:jaxb="http://java.sun.com/xml/ns/jaxb"
               jaxb:version="2.1"
               xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc"
               jaxb:extensionBindingPrefixes="xjc annox">

    <jaxb:bindings node="//xs:complexType[@name='Person']">
        <annox:annotate>
            <annox:annotate annox:class="javax.xml.bind.annotation.XmlRootElement" name="person"/>
        </annox:annotate>
    </jaxb:bindings>
</jaxb:bindings>

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