困难的JAXB映射 [英] Difficult JAXB mapping
问题描述
我试图在更大的文档中映射以下XML结构，显然这不是XML的最大用途，但这是我必须使用的。
I am trying to map the following XML structure within a larger document, clearly this isn't the greatest use of XML ever but this is what I have to work with.
为简洁起见，简化示例：
Example simplified for clarity:
<details>
<pictures>
<picture1>
http://domain.com/path/picture1.jpg
</picture1>
<picture2>
http://domain.com/path/picture2.jpg
</picture2>
<picture3>
http://domain.com/path/picture3.jpg
</picture3>
<picture4>
http://domain.com/path/picture4.jpg
</picture4>
<picture5>
http://domain.com/path/picture5.jpg
</picture5>
<picture6>
http://domain.com/path/picture6.jpg
</picture6>
<picture7>
http://domain.com/path/picture7.jpg
</picture7>
</pictures>
</details>
此文件有一个DTD，声明最多可有30个不同的图片元素，编号为1 -30名称< picutre [n] />
There is a DTD for this document which declares that there will be up to 30 different picture elements numbered 1-30 with the names <picutre[n]/>
我想做的是，而不是为每个元素创建30个不同的类，称为Picture1，Picture2，Picture3 ......等等。我只想使用一个Picture类并将其用于所有30个唯一元素名称。
What I would like to do is, rather than create 30 different classes for each of these elements called Picture1, Picture2, Picture3 ... and so on. I would just like to use a single Picture class and use it for all 30 unique element names.
以下是我到目前为止所尝试的内容。
Below is what I have tried so far.
@XmlRootElement
public class Details {
...
@XmlElementWrapper
@XmlElementRefs({
@XmlElementRef( name="picture1", type=Picture.class ),
@XmlElementRef( name="picture2", type=Picture.class ),
@XmlElementRef( name="picture3", type=Picture.class ),
@XmlElementRef( name="picture4", type=Picture.class ),
@XmlElementRef( name="picture5", type=Picture.class ),
@XmlElementRef( name="picture6", type=Picture.class ),
@XmlElementRef( name="picture7", type=Picture.class ),
@XmlElementRef( name="picture8", type=Picture.class ),
@XmlElementRef( name="picture9", type=Picture.class ),
@XmlElementRef( name="picture10", type=Picture.class ),
@XmlElementRef( name="picture11", type=Picture.class ),
@XmlElementRef( name="picture12", type=Picture.class ),
@XmlElementRef( name="picture13", type=Picture.class ),
@XmlElementRef( name="picture14", type=Picture.class ),
@XmlElementRef( name="picture15", type=Picture.class ),
@XmlElementRef( name="picture16", type=Picture.class ),
@XmlElementRef( name="picture17", type=Picture.class ),
@XmlElementRef( name="picture18", type=Picture.class ),
@XmlElementRef( name="picture19", type=Picture.class ),
@XmlElementRef( name="picture20", type=Picture.class ),
@XmlElementRef( name="picture21", type=Picture.class ),
@XmlElementRef( name="picture22", type=Picture.class ),
@XmlElementRef( name="picture23", type=Picture.class ),
@XmlElementRef( name="picture24", type=Picture.class ),
@XmlElementRef( name="picture25", type=Picture.class ),
@XmlElementRef( name="picture26", type=Picture.class ),
@XmlElementRef( name="picture27", type=Picture.class ),
@XmlElementRef( name="picture28", type=Picture.class ),
@XmlElementRef( name="picture29", type=Picture.class ),
@XmlElementRef( name="picture30", type=Picture.class )
})
public List<Picture> getPictures() {
return this.pictures;
}
public void setPictures( List<Pictures> pictures ) {
this.pictures = pictures;
}
...
}
@XmlElementWrapper
public class Picture {
...
}
这会导致getPictures始终返回null。
This causes getPictures to return null always.
另外，我尝试将Picture类的注释更改为 @XmlElementWrapper（name =picture1），这导致我从中返回一个列表getPictures（）但只包含< picture1 /> 元素，而不是其余元素。
Additionally I tried changing the annotation on the Picture class to be @XmlElementWrapper( name="picture1" ) which resulted in me getting a list returned from getPictures() but only ever containing the <picture1/> element and never the rest.
我知道我可以求助于获取JAXBElement对象的列表，但如果我可以避免它，我宁愿不这样做。我有什么想法可以映射这个吗？
I know I can resort to getting a list of JAXBElement objects instead but I would rather not if I can avoid it. Any ideas how I can map this?
推荐答案
有几种方法可以处理这个用例：
There are a couple ways you could handle this use case:
选项＃1
您可以通过利用 @XmlElements执行以下操作：
package forum10109418;
import java.util.List;
import javax.xml.bind.annotation.*;
@XmlRootElement
public class Details {
private List<Picture> pictures;
@XmlElementWrapper
@XmlElements({
@XmlElement( name="picture1", type=Picture.class ),
@XmlElement( name="picture2", type=Picture.class ),
@XmlElement( name="picture3", type=Picture.class ),
@XmlElement( name="picture4", type=Picture.class ),
@XmlElement( name="picture5", type=Picture.class ),
@XmlElement( name="picture6", type=Picture.class ),
@XmlElement( name="picture7", type=Picture.class ),
@XmlElement( name="picture8", type=Picture.class ),
@XmlElement( name="picture9", type=Picture.class ),
@XmlElement( name="picture10", type=Picture.class ),
@XmlElement( name="picture11", type=Picture.class ),
@XmlElement( name="picture12", type=Picture.class ),
@XmlElement( name="picture13", type=Picture.class ),
@XmlElement( name="picture14", type=Picture.class ),
@XmlElement( name="picture15", type=Picture.class ),
@XmlElement( name="picture16", type=Picture.class ),
@XmlElement( name="picture17", type=Picture.class ),
@XmlElement( name="picture18", type=Picture.class ),
@XmlElement( name="picture19", type=Picture.class ),
@XmlElement( name="picture20", type=Picture.class ),
@XmlElement( name="picture21", type=Picture.class ),
@XmlElement( name="picture22", type=Picture.class ),
@XmlElement( name="picture23", type=Picture.class ),
@XmlElement( name="picture24", type=Picture.class ),
@XmlElement( name="picture25", type=Picture.class ),
@XmlElement( name="picture26", type=Picture.class ),
@XmlElement( name="picture27", type=Picture.class ),
@XmlElement( name="picture28", type=Picture.class ),
@XmlElement( name="picture29", type=Picture.class ),
@XmlElement( name="picture30", type=Picture.class )
})
public List<Picture> getPictures() {
return this.pictures;
}
public void setPictures( List<Picture> pictures ) {
this.pictures = pictures;
}
}
选项＃2
您可以按如下方式映射详细信息类：
You could map your Details class as follows:
package forum10109418;
import java.util.List;
import javax.xml.bind.annotation.*;
@XmlRootElement
public class Details {
private List<Picture> pictures;
@XmlElementWrapper
@XmlElement(name="picture")
public List<Picture> getPictures() {
return this.pictures;
}
public void setPictures( List<Picture> pictures ) {
this.pictures = pictures;
}
}
然后使用 StreamReaderDelegate 切断数字后缀：
And then use a StreamReaderDelegate to chop off the numeric suffix:
package forum10109418;
import java.io.FileInputStream;
import javax.xml.bind.*;
import javax.xml.stream.*;
import javax.xml.stream.util.StreamReaderDelegate;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(Details.class);
XMLInputFactory xif = XMLInputFactory.newFactory();
XMLStreamReader xsr = xif.createXMLStreamReader(new FileInputStream("src/forum10109418/input.xml"));
xsr = new StreamReaderDelegate(xsr) {
@Override
public String getLocalName() {
String localName = super.getLocalName();
if(localName.startsWith("picture") && !localName.equals("pictures")) {
return "picture";
}
return localName;
}
};
Unmarshaller unmarshaller = jc.createUnmarshaller();
Details details = (Details) unmarshaller.unmarshal(xsr);
System.out.println(details.getPictures().size());
}
}
选项＃3
如果您使用的是 EclipseLink MOXy 作为您的 JAXB（JSR- 222） 提供商，然后您可以使用我们添加的 @XmlVariableNode 扩展程序：
If you are using EclipseLink MOXy as your JAXB (JSR-222) provider, then you could use the @XmlVariableNode extension that we added:
- http://blog.bdoughan.com/2013/06/mapping-bad-xml-enumerated-collection.html
这篇关于困难的JAXB映射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！
