动态地使用JAXB读取XML

Question

I am trying to extract the various fields of an various XMLs dynamically using JAXB. An example of one is as follows:

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?> 
<Entities TotalResults="1">
    <Entity Type="test-set-folder">
        <Fields>
            <Field Name="id">
                <Value>1760</Value> 
            </Field>
            <Field Name="ver-stamp">
                <Value>0</Value> 
            </Field>
            <Field Name="parent-id">
                <Value>109</Value> 
            </Field>
            <Field Name="last-modified">
                <Value>2017-02-24 15:50:36</Value> 
            </Field>
            <Field Name="hierarchical-path">
                <Value>AAAAAAABN</Value> 
            </Field>
            <Field Name="description">
                <Value /> 
            </Field>
            <Field Name="view-order" /> 
            <Field Name="name">
                <Value>ABCDEF</Value> 
            </Field>
            <Field Name="attachment">
                <Value /> 
            </Field>
            <Field Name="workflow">
                <Value /> 
            </Field>
        </Fields>
        <RelatedEntities /> 
    </Entity>
</Entities>

I want to do this dynamically as the fields change for every XML. My basic aim is to capture each field as use it for my convenience. For example, field.id should return 1760, etc.

My Entity.java is as follows:

import java.util.*;
import javax.xml.bind.annotation.*;
import javax.xml.namespace.QName;

@XmlRootElement(name = "Entities")
@XmlAccessorType(XmlAccessType.FIELD)
public class Entity {

    @XmlAttribute
    int id;

    @XmlAnyAttribute
    Map<QName, String> otherAttributes;

    String name;

    @XmlAnyElement(lax=true)
    List<Object> otherElements;

}

The code for calling Entity.java is as follows:

import java.io.File;
import java.util.Map.Entry;
import javax.xml.bind.*;
import javax.xml.namespace.QName;

public class Demo {

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

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("path\\to xml\\file");
        Entity entity  = (Entity) unmarshaller.unmarshal(xml);

        // Mapped XML Attribute
        System.out.println("entity.id");
        System.out.println("    " + entity.id);

        // Other XML Attributes
        System.out.println("entity.otherAttributes");
        for(Entry<QName, String> entry : entity.otherAttributes.entrySet()) {
            System.out.println("    " + entry);
        }

        // Mapped XML Element
        System.out.println("entity.name");
        System.out.println("    " + entity.name);

        // Other XML Elements
        System.out.println(entity.otherElements);
        for(Object object : entity.otherElements) {
            System.out.println("    " + object);
        }

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

}

My confusion is that the XML is nested, ie the fourth layer of data is what I'm interested in:

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?> 
<Entities TotalResults="1">
    <Entity Type="test-set-folder">
        <Fields>
            <Field Name="id">
                <Value>1760</Value> 
            </Field>
            .
            .
            .

My code for the Entity class is probably wrong, but can someone help me with how to go about it?

Answer 1

I think you must look at the below example where xml structure can vary and still you are able to load content using jaxB

XSD schema for xml file that can change for JAXB

Lets see if it works for you!