使用 Xpath 表达式和 jaxb 解组 XML [英] Unmarshalling an XML using Xpath expression and jaxb

问题描述

我是 JAXB 的新手，想知道是否有一种方法可以将 XML 解组到我的响应对象，但使用 xpath 表达式.问题是我正在调用第三方网络服务，我收到的响应有很多细节.我不希望将 XML 中的所有细节都映射到我的响应对象.我只想从 xml 中映射一些细节，我可以使用这些细节来使用特定的 XPath 表达式并将它们映射到我的响应对象.是否有注释可以帮助我实现这一目标?

I am new to JAXB and would like to know if there is a way by which I can unmarshall an XML to my response object but using xpath expressions. The issue is that I am calling a third party webservice and the response which I receive has a lot of details. I do not wish to map all the details in the XML to my response object. I just wish to map few details from the xml using which I can get using specific XPath expressions and map those to my response object. Is there an annotation which can help me achieve this?

例如考虑以下响应

<root>
  <record>
    <id>1</id>
    <name>Ian</name>
    <AddressDetails>
      <street> M G Road </street>
    </AddressDetails>
  </record>  
</root>

我只对检索街道名称感兴趣，所以我想使用 xpath 表达式来使用root/record/AddressDetails/street"获取街道的值并将其映射到我的响应对象

I am only intrested in retrieving the street name so I want to use xpath expression to get value of street using 'root/record/AddressDetails/street' and map it to my response object

public class Response{
     // How do i map this in jaxb, I do not wish to map record,id or name elements
     String street; 

     //getter and setters
     ....
}   

谢谢

推荐答案

注意:我是EclipseLink JAXB (MOXy) 领导和成员 JAXB (JST-222) 专家组.

Note: I'm the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JST-222) expert group.

您可以在此用例中使用 MOXy 的 @XmlPath 扩展.

You could use MOXy's @XmlPath extension for this use case.

回复

import javax.xml.bind.annotation.*;
import org.eclipse.persistence.oxm.annotations.XmlPath;

@XmlRootElement(name="root")
@XmlAccessorType(XmlAccessType.FIELD)
public class Response{
    @XmlPath("record/AddressDetails/street/text()")
    String street; 

    //getter and setters
}

jaxb.properties

要将 MOXy 用作您的 JAXB 提供程序，您需要在与域模型相同的包中包含一个名为 jaxb.properties 的文件，其中包含以下条目(请参阅:http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html)

To use MOXy as your JAXB provider you need to include a file called jaxb.properties in the same package as your domain model with the following entry (see: http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html)

javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory

演示

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

public class Demo {

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

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum17141154/input.xml");
        Response response = (Response) unmarshaller.unmarshal(xml);

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

}

输出

<?xml version="1.0" encoding="UTF-8"?>
<root>
   <record>
      <AddressDetails>
         <street> M G Road </street>
      </AddressDetails>
   </record>
</root>

了解更多信息

• http://blog.bdoughan.com/2010/07/xpath-based-mapping.html
• http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html

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