使用MOXy和XPath，是否可以解组属性列表？ [英] With MOXy and XPath, is it possible to unmarshal a list of attributes?

问题描述

编辑：这是我加载XML文档的方式，就像我在Blaise的回答中使用的那样。我正在加载它，因为我想使用节点，而不是整个文档。即使使用整个文档，我在以这种方式加载时仍然遇到问题。

here's how I'm loading the XML document, as I used it in Blaise's answer. I'm loading it like this because I want to work with a node, not the whole doc. Even using the whole document I'm still having trouble when loading in this manner.

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(false);
factory.setNamespaceAware(false);
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("[path to doc]/input.xml");
TestClass testClass = (TestClass) unmarshaller.unmarshal(doc);

我的XML看起来像这样：

I've got XML that looks like this:

<test>
  <items>
    <item type="cookie">cookie</item>
    <item type="crackers">crackers</item>
  </items>
</test>

一个班级：

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "test")
public class TestClass
{
  @XmlPath("items/item/text()")
  @XmlElement
  private ArrayList<String> itemList = new ArrayList<String>();

  // getters, setters omitted
}

以上代码将起作用，无论我是否有 @XmlElement ，我得到一个包含[cookie，crackers]的ArrayList。

The above code will work whether or not I have @XmlElement, and I get an ArrayList containing [cookie, crackers].

如果我将上面的声明更改为

If I change the declaration above to

@XmlPath("items/item/@type")
@XmlElement
private ArrayList<String> itemList = new ArrayList<String>();

我的ArrayList为空。

my ArrayList is empty.

我的最终目标是拥有属性，以便我的XML看起来像这样：

My ultimate goal is to just have attributes so my XML would look like this:

<test>
  <items>
    <item type="cookie"/>
    <item type="crackers"/>
  </items>
</test>

我正在尝试做什么，使用XPath提取属性列表，可能，以及如果是这样，怎么样？

Is what I'm trying to do, pull out a list of attributes using XPath, possible, and if so, how?

谢谢。

推荐答案

更新

我已经能够确认您所看到的问题（ https://bugs.eclipse.org/353763 ）。我们的EclipseLink 2.3.1和2.4.0流中添加了一个修复程序，可以从2011年8月4日开始的每晚下载页面获得：

I have been able to confirm the issue you are seeing (https://bugs.eclipse.org/353763). A fix has been added into our EclipseLink 2.3.1 and 2.4.0 streams and can be obtained from the nightly download page starting August 4th, 2011:

• http://www.eclipse.org/eclipselink/downloads/nightly.php

• http://www.eclipse.org/eclipselink/downloads/nightly.php

解决方法：

您可以通过将 DocumentBuilderFactory 设置为名称空间来解决此问题：

You can workaround this issue by setting your DocumentBuilderFactory to be namespace aware:

    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    factory.setNamespaceAware(true);
    DocumentBuilder builder = factory.newDocumentBuilder();
    Document doc = builder.parse("src/forum6907225/input.xml");
    testClass = (TestClass) unmarshaller.unmarshal(doc);
    marshaller.marshal(testClass, System.out);

---

您正在正确进行映射（见下文） ）。您是否已包含jaxb.properties文件以指定 EclipseLink MOXy 作为您的JAXB提供程序？：

---

You are doing the mapping correctly (see below). Have you included a jaxb.properties file to specify EclipseLink MOXy as your JAXB provider?:

• http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html

• http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html

测试类

package forum6907225;

import java.util.ArrayList;

import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

import org.eclipse.persistence.oxm.annotations.XmlPath;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "test")
public class TestClass
{
    @XmlPath("items/item/@type")
    @XmlElement
    private ArrayList<String> itemList = new ArrayList<String>();

  // getters, setters omitted
}

演示

package forum6907225;

import java.io.File;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

import org.eclipse.persistence.Version;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(TestClass.class);
        System.out.println(Version.getVersionString());

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum6907225/input.xml");
        TestClass testClass = (TestClass) unmarshaller.unmarshal(xml);

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

}

input.xml

<?xml version="1.0" encoding="UTF-8"?>
<test>
  <items>
    <item type="cookie">cookie</item>
    <item type="crackers">crackers</item>
  </items>
</test>

输出

2.3.1.qualifier
<?xml version="1.0" encoding="UTF-8"?>
<test>
   <items>
      <item type="cookie"/>
      <item type="crackers"/>
   </items>
</test>

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