如何在XSD中为基类型生成@XmlRootElement类？ [英] How to generate @XmlRootElement Classes for Base Types in XSD?

问题描述

我在使用XJC从XSD生成带有适当JAXB注释的Java类时遇到一些问题。

I am having some issues with generating Java Classes with appropriate JAXB annotations from an XSD using XJC.

我有一个相对简单的XSD文件来定义我的XML模式。 XSD中的复杂类型利用< xs：extension> 标记继承。我遇到的问题是我需要所有复杂类型来生成带有 @XmlRootElement 的Java类。

I have a relatively simple XSD file defining my XML schema. The complex types within the XSD take advantage of inheritance using the <xs:extension> tags. The problem I having is that I need all complex types to generate Java Classes with the @XmlRootElement.

不幸的是，XJC生成类的方式意味着只有派生类才能获得 @XmlRootElement （不是基类）。我使用简单的全局绑定指令来确保它解决了我在XJC面临的许多其他问题。

Unfortunately, the way in which XJC generates the classes means that only derived class gets the @XmlRootElement (not the base class). I am using the simple global binding directive to ensure that it solves many of the other issues that I have faced with XJC.

以下是XSD的示例片段：

Here is an example snippet of the XSD:

<xs:schema version="1.0" targetNamespace="http://www.knowledgemill.com/kmcs"
  xmlns:kmcs="http://www.knowledgemill.com/kmcs"
  xmlns:xs="http://www.w3.org/2001/XMLSchema"
  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"
  elementFormDefault="qualified">
    <xs:annotation>
        <xs:appinfo>
            <jaxb:globalBindings>
                <xjc:simple />
            </jaxb:globalBindings>
        </xs:appinfo>
    </xs:annotation>

    <xs:element name="Artifact" type="kmcs:Artifact"/>
    <xs:element name="EmailArtifact" type="kmcs:EmailArtifact"/>

    <xs:complexType name="Artifact">
        <xs:sequence>
            <xs:element name="artifactId" type="xs:string" minOccurs="0"/>
            <xs:element name="artifactType" type="xs:string" minOccurs="0"/>
            <xs:element name="contentHash" type="xs:string" minOccurs="0"/>
        </xs:sequence>
    </xs:complexType>

    <xs:complexType name="EmailArtifact">
        <xs:complexContent>
            <xs:extension base="kmcs:Artifact">
                <xs:sequence>
                    <xs:element name="subject" type="xs:string" minOccurs="0"/>
                    <xs:element name="threadSubject" type="xs:string" minOccurs="0"/>
                    <xs:element name="from" type="xs:string" minOccurs="0"/>
                    <xs:element name="to" type="xs:string" minOccurs="0"/>
                    <xs:element name="cc" type="xs:string" minOccurs="0"/>
                    <xs:element name="bcc" type="xs:string" minOccurs="0"/>
                    <xs:element name="messageId" type="xs:string" minOccurs="0"/>
                    <xs:element name="date" type="xs:date" minOccurs="0"/>
                    <xs:element name="size" type="xs:long" minOccurs="0"/>
                    <xs:element name="hasAttachment" type="xs:boolean" minOccurs="0"/>
                    <xs:element name="sensitivity" type="xs:string" minOccurs="0"/>
                    <xs:element name="headerHash" type="xs:string" minOccurs="0"/>
                </xs:sequence>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>


</xs:schema>

正如我们从上面的代码片段中看到的， EmailArtifact extends Artifact 。

As we can see from the above snippet, EmailArtifact extends Artifact.

EmailArtifact 的java类代码包含以下内容：

The java class code for EmailArtifact contains the following:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "EmailArtifact", propOrder = {
    "subject",
    "threadSubject",
    "from",
    "to",
    "cc",
    "bcc",
    "messageId",
    "date",
    "size",
    "hasAttachment",
    "sensitivity",
    "headerHash"
})
@XmlSeeAlso({
    ExtendedEmail.class
})
@XmlRootElement(name = "EmailArtifact")
public class EmailArtifact
    extends Artifact
{

    protected String subject;
    protected String threadSubject;
    protected String from;
    protected String to;
    protected String cc;
    protected String bcc;
    protected String messageId;
    @XmlSchemaType(name = "date")
    protected XMLGregorianCalendar date;
    protected Long size;
    protected Boolean hasAttachment;
    protected String sensitivity;
    protected String headerHash;

Artifact 的java类代码包含以下：

The java class code for Artifact contains the following:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "Artifact", propOrder = {
    "artifactId",
    "artifactType",
    "contentHash"
})
@XmlSeeAlso({
    ManagedDocArtifact.class,
    EmailArtifact.class
})
public class Artifact {

    protected String artifactId;
    protected String artifactType;
    protected String contentHash;

在 EmailArtifact 中，我们可以看到它包含 @XmlRootElement 但基本类型工件不包含 @XmlRootElement 。

In the EmailArtifact we can see that it contains the @XmlRootElement but the base type Artifact does not contain @XmlRootElement.

如何强制XJC为所有类（包括基类型）生成 @XmlRootElement 。

How can you force XJC to generate @XmlRootElement for all classes including the base types.

推荐答案

使用xjb文件进行绑定：

Just bind using xjb-file:

<?xml version="1.0"?>
<jxb:bindings version="1.0" xmlns:jxb="http://java.sun.com/xml/ns/jaxb" xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc" jxb:extensionBindingPrefixes="xjc" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <jxb:bindings schemaLocation="path/to/myschema.xsd" node="/xs:schema">
    <jxb:globalBindings>
      <xjc:simple />
    </jxb:globalBindings>
  </jxb:bindings>
</jxb:bindings>

并且不要忘记定义相同类型的元素：

And don't forget to define element of the same type:

<xs:complexType name="Artifact" />
<xs:element name="artifact" type="Artifact">

这篇关于如何在XSD中为基类型生成@XmlRootElement类？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！