通过JAXB解组XML

Question

I have a xml as follows:

<VisitorDataList>
  <VisitorData>
   <Attribute1List>
            <Attribute1>
                <Attribute1Name>name1</Attribute1Name>
                <Attribute1Id>2</Attribute1Id>
            </Attribute1>
            <Attribute1>
                <Attribute1Name>name1</Attribute1Name>
                <Attribute1Id>3</Attribute1Id>
            </Attribute1>
            <Attribute1>
                <Attribute1Name>name1</Attribute1Name>
                <Attribute1Id>1</Attribute1Id>
            </Attribute1>
        </Attribute1List>
     <Attribute2List>
            <Attribute2>
                <Attribute2Name>name2</Attribute2Name>
                <Attribute2Id>113</Attribute2Id>
            </Attribute2>
            <Attribute2>
                <Attribute2Name>name2</Attribute2Name>
                <Attribute2Id>115</Attribute2Id>
            </Attribute2>
            <Attribute2>
                <Attribute2Name>name2</Attribute2Name>
                <Attribute2Id>114</Attribute2Id>
            </Attribute2>
        </Attribute2List>
  </VisitorData>
 </VisitorDataList> 

The Attribute1List and Attribute2List is dynamic for both name and value, so they can be Attribute3List or Attribute4List and so on. Now i want to parse this xml via jAXB, the java bean is like:

@XmlRootElement(name = "VisitorDataList")
public class VisitorDataList {

    @XmlElement(name = "VisitorData")
    public List<Visitor> getVisitors() {
        return visitors;
    }

    public void setVisitors(List<Visitor> visitors) {
        this.visitors = visitors;
    }

}

public class Visitor {

    private List<String> attributes= new ArrayList<String>();

        public List<String> getAttributes() {
        return attributes;
    }

    public void setAttributes(List<String> attributes) {
        this.attributes= attributes;
    }
}

My question is how to map all the attribute names into one list? Thanks in advance.

Answer 1

You could use JAXB to unmarshal from StAX with a StreamReaderDelegate to strip off the number from the element names. Your JAXB mappings will then be made to elements

Below is a link to an article I wrote where I use this approach to do case insensitive unmarshalling:

• http://blog.bdoughan.com/2010/12/case-insensitive-unmarshalling.html

---

Java Model

VistorDataList

import java.util.List;

import javax.xml.bind.annotation.*;

@XmlRootElement(name = "VisitorDataList")
public class VisitorDataList {

    private List<Visitor> visitors;

    @XmlElementWrapper(name="VisitorData")
    @XmlElement(name = "AttributeList")
    public List<Visitor> getVisitors() {
        return visitors;
    }

    public void setVisitors(List<Visitor> visitors) {
        this.visitors = visitors;
    }

}

Visitor

import java.util.*;
import javax.xml.bind.annotation.XmlElement;

public class Visitor {

    private List<String> attributes = new ArrayList<String>();

    @XmlElement(name="AttributeName")
    public List<String> getAttributes() {
        return attributes;
    }

    public void setAttributes(List<String> attributes) {
        this.attributes = attributes;
    }

}

Demo Code

Demo

import javax.xml.bind.*;
import javax.xml.stream.*;
import javax.xml.stream.util.StreamReaderDelegate;
import javax.xml.transform.stream.StreamSource;

public class Demo {

    public static void main(String[] args) throws Exception {
        XMLInputFactory xif = XMLInputFactory.newFactory();
        StreamSource xml = new StreamSource("src/forum18071557/input.xml");
        XMLStreamReader xsr = xif.createXMLStreamReader(xml);

        xsr = new StreamReaderDelegate(xsr) {

            @Override
            public String getLocalName() {
                String localName = super.getLocalName();
                if(localName.startsWith("Attribute") && localName.endsWith("List")) {
                    return "AttributeList";
                } else if(localName.startsWith("Attribute") && localName.endsWith("Name")) {
                    return "AttributeName";
                } else if(localName.startsWith("Attribute")) {
                    return "ignore";
                } else {
                    return localName;
                }
            }

        };

        xsr = xif.createFilteredReader(xsr, new StreamFilter() {
            @Override
            public boolean accept(XMLStreamReader reader) {
                if(reader.isStartElement() || reader.isEndElement()) {
                    return !reader.getLocalName().equals("ignore");
                } else {
                    return true;
                }
            }

        });

        JAXBContext jc = JAXBContext.newInstance(VisitorDataList.class);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        VisitorDataList vdl = (VisitorDataList) unmarshaller.unmarshal(xsr);

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

}

Output

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<VisitorDataList>
    <VisitorData>
        <AttributeList>
            <AttributeName>name1</AttributeName>
            <AttributeName>name1</AttributeName>
            <AttributeName>name1</AttributeName>
        </AttributeList>
        <AttributeList>
            <AttributeName>name2</AttributeName>
            <AttributeName>name2</AttributeName>
            <AttributeName>name2</AttributeName>
        </AttributeList>
    </VisitorData>
</VisitorDataList>

Answer 2

I tried your XML file to unmarshal using JAXB but I was only able to parse it statically.You can try it once.

visitor.xml

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<VisitorDataList>
  <VisitorData>
   <AttributeList>
            <Attribute>
                <AttributeName>name1</AttributeName>
                <AttributeId>2</AttributeId>
            </Attribute>
            <Attribute>
                <AttributeName>name1</AttributeName>
                <AttributeId>3</AttributeId>
            </Attribute>
            <Attribute>
                <AttributeName>name1</AttributeName>
                <AttributeId>1</AttributeId>
            </Attribute>
        </AttributeList>
     <AttributeList>
            <Attribute>
                <AttributeName>name2</AttributeName>
                <AttributeId>113</AttributeId>
            </Attribute>
            <Attribute>
                <AttributeName>name2</AttributeName>
                <AttributeId>115</AttributeId>
            </Attribute>
                <Attribute>
                <AttributeName>name2</AttributeName>
                <AttributeId>114</AttributeId>
            </Attribute> 
        </AttributeList>
  </VisitorData>

visitordatalist.java

package foo.bar.me.too;

import java.util.List;

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

@XmlRootElement(name="VisitorDataList")
public class visitordatalist {


    List<visitordata> vstd;



    @XmlElement(name="VisitorData")
    public List<visitordata> getVstd() {
        return vstd;
    }

    public void setVstd(List<visitordata> vstd) {
        this.vstd = vstd;
    }



}

visitordata.java

package foo.bar.me.too;

import java.util.List;

import javax.xml.bind.annotation.XmlElement;

public class visitordata {

    List<attributelist> atrl;


    public String toString() {
        return atrl.toString();
    }

    @XmlElement(name="AttributeList")
     public List<attributelist> getAtrl() {
        return atrl;
    }
    public void setAtrl(List<attributelist> atrl) {
        this.atrl = atrl;
    }


}

attributelist.java

package foo.bar.me.too;

import java.util.List;

import javax.xml.bind.annotation.XmlElement;

public class attributelist {

    List<attribute> atr;
     public String toString() {
            return atr.toString();
        }

     @XmlElement(name="Attribute")
    public List<attribute> getAtr() {
        return atr;
    }

    public void setAtr(List<attribute> atr) {
        this.atr = atr;
    }

    }

attribute.java

package foo.bar.me.too;

import javax.xml.bind.annotation.XmlElement;

public class attribute {

    String atrName;
    String atrId;

     public String toString() {
            return atrName+"   "+atrId;

        }


    @XmlElement(name="AttributeName")
    public String getAtrName() {
        return atrName;
    }
    public void setAtrName(String atrName) {
        this.atrName = atrName;
    }

    @XmlElement(name="AttributeId")
    public String getAtrId() {
        return atrId;
    }
    public void setAtrId(String atrId) {
        this.atrId = atrId;
    }


 }      

JAXBExample.java

package foo.bar.me.too;

import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;

public class JAXBExample {
    public static void main(String[] args) {

     try {

        File file = new File("visitor.xml");
        JAXBContext jaxbContext = JAXBContext.newInstance(visitordatalist.class);

        Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
        visitordatalist  vstdl = (visitordatalist) jaxbUnmarshaller.unmarshal(file);

        System.out.println(vstdl.getVstd());

      } catch (JAXBException e) {
        e.printStackTrace();
      }

    }

}

Answer 3

There is a special arcane knowledge for some special JAXB implementations. For example, for FasterXML (used in WildFly) you should change one property to make it work (just override an additional method in Delegator):

@Override
public Object getProperty(String name) {
    Object property = super.getProperty(name);
    if("org.codehaus.stax2.internNames".equals(name)) {
        return Boolean.FALSE;
    }
    return property;
}