对于具有命名空间的属性,JAXB返回null

Question

例如,我需要解组具有属性名称空间的XML

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

该属性定义为

@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null.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")但它也没用.

XML文件的顶部是:

<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">

Answer 1

namespace下面是如何在注释上指定属性的示例@XmlAttribute。

输入.xml

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

执照

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？

如果您想控制将文档编组到 XML 时使用的命名空间前缀，请查看以下文章：

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