如何让 jaxb 在解组期间忽略某些数据 [英] How to get jaxb to Ignore certain data during unmarshalling

问题描述

我有一个 xml 结构过滤器"，它被解组到一个名为过滤器"的 java 类中.

I have a xml structure "Filter" that get unmarshalled into in a java class called "Filter".

XML 状态大致如下:

The XML state looks roughly like:

<filter>
  <propertyType>
    <propertyName>prop1</propertyName>
    <propertyValue>val1</propertyValue>
  </propertyType>
  <propertyType>
    <propertyName>prop2</propertyName>
    <propertyValue>val2</propertyValue>
  </propertyType>
</filter>

通常，它工作得很好.

但是，在某些情况下，这些属性值之一本身包含 xml 结构(请参阅下面的第二个 propertyValue):

However, there are certain situations where one of these property values itself contains xml structure (see second propertyValue below):

<filter>
  <propertyType>
    <propertyName>prop1</propertyName>
    <propertyValue>val1</propertyValue>
  </propertyType>
  <propertyType>
    <propertyName>prop2</propertyName>
    <propertyValue><nodeA><nodeB>valB</nodeB></nodeA></propertyValue>
  </propertyType>
</filter>

这里的问题是，解组这个结构后，propertyValue为null.

The problem here is that after unmarshalling this structure, the propertyValue is null.

我希望能够让解组忽略这个看起来像 xml 的代码并将其视为一个简单的字符串值.

I would like to simply be able to have the unmarshalling ignore this xml-looking code and treat it as a simple string value.

有谁知道我如何做到这一点?感谢您的回复！

Does anyone know how I can accomplish this? Thanks for any reply!

推荐答案

对于这个用例，我将创建一个将转换 XML 文档的 XSLT.然后使用 javax.xml.transform.* API，将 XML 转换为 JAXBResult 以解组对象:

For this use case I would create an XSLT that will convert the XML document. Then using the javax.xml.transform.* APIs, transform the XML to a JAXBResult to unmarshal the object:

import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.util.JAXBResult;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamSource;

public class Demo {

    public static void main(String[] args) throws Exception {
        TransformerFactory tf = TransformerFactory.newInstance();

        File xsltFile = new File("transform.xsl");
        StreamSource xsltSource = new StreamSource(xsltFile);
        Transformer transformer = tf.newTransformer(xsltSource);

        File xml = new File("input.xml");
        StreamSource xmlSource = new StreamSource(xml);

        JAXBContext jc = JAXBContext.newInstance(Filter.class);
        JAXBResult jaxbResult = new JAXBResult(jc);

        transformer.transform(xmlSource, jaxbResult);

        Filter filter = (Filter) jaxbResult.getResult();
    }

}

transform.xsl

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:template match="node() | @*">
        <xsl:copy>
            <xsl:apply-templates select="node() | @*" />
        </xsl:copy>
    </xsl:template>
    <xsl:template match="propertyValue"> <xsl:value-of select="descendents"/>
       <xsl:element name="propertyValue">
           <xsl:value-of select="node()"/>
       </xsl:element>
    </xsl:template>
</xsl:stylesheet>

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