JAXB可映射XML元素

Question

在我的xi-schema的root.class中，元素item和其他對象是itemList的一部分：

@XmlElementRef(name = "item", namespace = "xi", type = JAXBElement.class, required = false) 
//...
protected List<Object> itemList;

我從主模式進入ObjectFactory.class ，將某些項目作為JAXBElements像這樣：

@XmlElementDecl(namespace = "de-schema", name = "detailedInformation", substitutionHeadNamespace = "xi", substitutionHeadName = "item")
public JAXBElement<numItemType> createDetailedInformation(numItemType num) {
    return new JAXBElement<numItemType>(_detailedInformation_QNAME, numItemType.class, null, num);
}

因此numItemType具有JAXBElement一些屬性和value（num）。

NumItemType.class：

@XmlJavaTypeAdapter(numItemTypeAdapter.class)
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "numItemType", namespace = "xi", propOrder = {
    "num"
})

public class NumItemType {

    @XmlValue
    protected BigDecimal num;
    @XmlAttribute(name = "precision")
    protected String precision;
    @XmlAttribute(name = "decimals")
    protected String decimals;
    //... more Attributes

}

但是當JAXB解組XML文檔時，它將僅包含元素，例如：

<detailedInformation>
    <element1>1234</element1>
    <element2>5678</element2>
    <element3>bla</element3>
</detailedInformation>

當我編組它時，它應該變成（就像JAXB Java代碼一樣）：

<detailedInformation element2="5678" element3="bla">1234</detailedInformation>

因此，我用NumItemTypeAdapter擴展了XmlAdapter編寫了一個numItemTypeAdapter.class

AdaptedNum.class：

public class AdaptedNum {
    @XmlElement 
    private  double element1;
    @XmlElement
    private String element2;
    @XmlElement
    private String element3;

   /** Some getter/setter methods */
}

我認為，這將對我有所幫助http://blog.bdoughan.com/2012/02/xmlanyelement-and-xmladapter.html ，但這有點棘手：-/

Answer 1

准確地找出問題可能發生的位置有些棘手。 我假設您的原始模型是從XML Schema生成的，這應該可以不做任何修改地按原樣工作。 我在下面嘗試提供示例的按比例縮小版本，這可能會有所幫助。

根

package forum11343610;

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

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Root {

    @XmlElementRef(name = "item", namespace = "xi", type = JAXBElement.class, required = false) 
    protected List<Object> itemList = new ArrayList<Object>();

    public List<Object> getItemList() {
        return itemList;
    }

    public void setItemList(List<Object> itemList) {
        this.itemList = itemList;
    }

}

NumItemType

package forum11343610;

import java.math.BigDecimal;
import javax.xml.bind.annotation.*;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "numItemType", namespace = "xi", propOrder = {
    "num"
})

public class NumItemType {

    @XmlValue
    protected BigDecimal num;
    @XmlAttribute(name = "precision")
    protected String precision;
    @XmlAttribute(name = "decimals")
    protected String decimals;
    //... more Attributes

}

對象工廠

package forum11343610;

import javax.xml.bind.JAXBElement;
import javax.xml.bind.annotation.*;
import javax.xml.namespace.QName;

@XmlRegistry
public class ObjectFactory {

    private static final QName _detailedInformation_QNAME = new QName("de-schema", "detailedInformation");

    @XmlElementDecl(namespace = "xi", name = "item")
    public JAXBElement<NumItemType> createItem(NumItemType num) {
        return new JAXBElement<NumItemType>(_detailedInformation_QNAME, NumItemType.class, null, num);
    }

    @XmlElementDecl(namespace = "de-schema", name = "detailedInformation", substitutionHeadNamespace = "xi", substitutionHeadName = "item")
    public JAXBElement<NumItemType> createDetailedInformation(NumItemType num) {
        return new JAXBElement<NumItemType>(_detailedInformation_QNAME, NumItemType.class, null, num);
    }

}

演示版

package forum11343610;

import java.math.BigDecimal;
import javax.xml.bind.*;

public class Demo {

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

        ObjectFactory objectFactory = new ObjectFactory();
        Root root = new Root();

        NumItemType numItemType = new NumItemType();
        numItemType.num = BigDecimal.TEN;
        numItemType.decimals = "1";
        numItemType.precision = "2";
        root.getItemList().add(objectFactory.createDetailedInformation(numItemType));

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

}

輸出量

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<root xmlns:ns2="de-schema" xmlns:ns3="xi">
    <ns2:detailedInformation precision="2" decimals="1">10</ns2:detailedInformation>
</root>

Answer 2

感謝您的評論。

這才是重點：

演示版

NumItemType numItemType = new NumItemType();
numItemType.num = BigDecimal.TEN;
numItemType.decimals = "1";
numItemType.precision = "2";
root.getItemList().add(objectFactory.createDetailedInformation(numItemType));

它應該解組並自動映射XML。

XML輸入

<detailedInformation>
     <element1>1234</element1>
     <element2>5678</element2>
     <element3>bla</element3>
</detailedInformation>

使用代碼：

演示版

JAXBContext jc = JAXBContext.newInstance(Root.class, ObjectFactory.class);
Unmarshaller u = jc.createUnmarshaller();
File xml = new File("D:/", "test.xml");
Root root = (Root) u.unmarshal(xml);

輸出量

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<root xmlns:ns2="de-schema" xmlns:ns3="xi">
    <ns2:detailedInformation precision="2" decimals="1">10</ns2:detailedInformation>
</root>

我可以將帶有DOM的XML文檔解析為一棵樹並使用JAXB進行編組...

謝謝！

Answer 3

換一種說法：

我想在不更改架構Java代碼的情況下將新元素設置為NumItemType.class進行編組。

NumItemType.class

package forum11343610;

import java.math.BigDecimal;
import javax.xml.bind.annotation.*;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "numItemType", namespace = "xi", propOrder = {
    "num"
})

    @XmlJavaTypeAdapter(NumItemTypeAdapter.class)
    public class NumItemType {

        @XmlValue
        protected BigDecimal num;
        @XmlAttribute(name = "precision")
        protected String precision;
        @XmlAttribute(name = "decimals")
        protected String decimals;
        //... more Attributes

    }

NumItemTypeAdapter.class

public  class NumItemTypeAdapter extends XmlAdapter<AdaptedNum, NumItemType> {

    @Override
    public NumItemType unmarshal(AdaptedNum an) throws Exception {
        NumItemType nit = new NumItemType();
        nit.setNum(an.getNum);
        nit.setPrecision(an.getPrecision);
        nit.setDecimals(an.getDecimals)
        return nit;
    }

}

AdaptedNum.class

    @XmlAccessorType(XmlAccessType.FIELD)
    @XmlType(name = "adaptedNum", namespace = "", propOrder = {
        "element1",
        "element2",
        "element3"
    })

    public class AdaptedNum {

        @XmlElement(name ="element1")
        protected  BigDecimal num;
        @XmlElement(name ="element2")
            private String decimals;
        @XmlElement(name ="element3")
            private String precison;
            // set/get method
}