对于具有命名空间的属性，JAXB返回null [英] JAXB returns null for attributes with a namespace

问题描述

我需要解组具有属性名称空间的XML，例如

I need to unmarshall an XML that has namespaces for the attributes, for instance

<license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by/2.0/uk/"><license-p>

此属性定义为

@XmlAttribute(namespace = "http://www.w3.org/TR/xlink/")  
@XmlSchemaType(name = "anySimpleType")  
protected String href;  

但是当我尝试检索href时，它为空。我应该添加/修改jaxb代码以获得正确的值？我已经尝试避免名称空间，但它不起作用，仍为null。我也试过 @XmlAttribute（namespace =http://www.w3.org/TR/xlink/，name =href）但它没有用无论是。

But when I try to retrieve the href, it is null. What should I add/modify to the jaxb code in order to get the right value? I already tried to avoid namespaces but it did not work, still null. I also tried with @XmlAttribute(namespace = "http://www.w3.org/TR/xlink/", name = "href") but it did not work either.

XML文件的顶部是：

The top of the XML file is:

<DOCTYPE article
  PUBLIC "-//NLM//DTD v3.0 20080202//EN" "archive.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mml="http://www.w3.org/1998/Math/MathML" article-type="article">

推荐答案

以下是如何指定<$的示例 @XmlAttribute 注释中的c $ c> namespace 属性。

Below is an example of how to specify the namespace property on the @XmlAttribute annotation.

input.xml

<article xmlns:xlink="http://www.w3.org/1999/xlink">
    <license xlink:href="http://creativecommons.org/licenses/by/2.0/uk/"/>
</article>

许可证

package forum10566766;

import javax.xml.bind.annotation.XmlAttribute;

public class License {

    private String href;

    @XmlAttribute(namespace="http://www.w3.org/1999/xlink")
    public String getHref() {
        return href;
    }

    public void setHref(String href) {
        this.href = href;
    }

}

文章

package forum10566766;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Article {

    private License license;

    public License getLicense() {
        return license;
    }

    public void setLicense(License license) {
        this.license = license;
    }

}

演示

package forum10566766;

import java.io.File;
import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Article.class);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum10566766/input.xml");
        Article article = (Article) unmarshaller.unmarshal(xml);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(article, System.out);
    }

}

输出

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<article xmlns:ns1="http://www.w3.org/1999/xlink">
    <license ns1:href="http://creativecommons.org/licenses/by/2.0/uk/"/>
</article>

想要控制命名空间前缀？

如果要控制将文档编组为XML时使用的名称空间前缀，请查看以下文章：

If you want to control the namespace prefixes used when the document is marshalled to XML check out the following article:

• http://blog.bdoughan.com/2011/11 /jaxb-and-namespace-prefixes.html

• http://blog.bdoughan.com/2011/11/jaxb-and-namespace-prefixes.html

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