JAXB解组问题（获取空列表）

Question

我正试图使用JAXB api解析下面的XML文档，我想解析PROPERTYDATALIST中包含多个PROPERTYDATA对象的每个项。在文档解组过程中，我得到一个空列表。任何关于如何解决此问题的帮助都将不胜感激。

<?xml version="1.0" encoding="UTF-8"?>
<FACILITY>
    <ARRANGEMENTACTIVITY>
        <ID>NEW</ID>
        <CUSTOMER>500000030</CUSTOMER>
        <CUSTOMERROLE>OWNER</CUSTOMERROLE>      
        <PROPERTYDATALIST>
            <PROPERTYDATA>
                <PROPERTY>FACOMMITMENT</PROPERTY>
                <AMOUNT>600000</AMOUNT>
                <TERM>5Y</TERM>
                <MATURITYDATE>20261001</MATURITYDATE>
            </PROPERTYDATA>
            <PROPERTYDATA>
                <PROPERTY>PRINCIPALINT</PROPERTY>
                <FIXEDRATE>3.5</FIXEDRATE>
            </PROPERTYDATA>         
        </PROPERTYDATALIST>
    </ARRANGEMENTACTIVITY>
</FACILITY>

下面是我编写的用于解组XML文件的类

@XmlRootElement(name = "FACILITY")
@Data
@NoArgsConstructor
@XmlAccessorType(XmlAccessType.FIELD)
public class Facility {
    @XmlElement(name = "ARRANGEMENTACTIVITY")
    private ArrangementActivity arrangementActivity;
    
}

@XmlAccessorType(XmlAccessType.NONE)
@XmlType(propOrder = {"id", "customer","propertyDataList", "application", "version", "operation"})
@Data
public class ArrangementActivity {

    @XmlElement(name = "APPLICATION")
    private String application;
    
    @XmlElement(name = "VERSION")
    private String version;
    
    @XmlElement(name = "OPERATION")
    private String operation;
    
    @XmlElement(name = "ID")
    private String id;
    
    @XmlElement(name = "CUSTOMER")
    private String customer;    
    
    @XmlElementWrapper(name = "PROPERTYDATALIST")
    @XmlElement(name = "PROPERTYDATALIST")
    private List<PropertyData> propertyDataList;    
}

@XmlAccessorType(XmlAccessType.NONE)
@Data
@XmlType(propOrder = {"property", "amount", "term", "maturityDate", "fixedRate" })
public class PropertyData {
    
    @XmlElement(name = "PROPERTY")
    private String property;
    
    @XmlElement(name = "AMOUNT")
    private String amount;
    
    @XmlElement(name = "TERM")
    private String term;
    
    @XmlElement(name = "MATURITYDATE")
    private String maturityDate;
    
    @XmlElement(name = "FIXEDRATE")
    private String fixedRate;
        
}

public class JaxbExampleMain {

    public static void main(String[] args) {
    
        String fileSourcePath = // file path";
        try {
            
            File file = new File( fileSourcePath);              
            InputStream inputStream = new FileInputStream(file); 
                
            final XMLStreamReader xmlStreamReader = XMLInputFactory.newInstance().createXMLStreamReader(inputStream);
            final Unmarshaller unmarshaller = JAXBContext.newInstance(Facility.class).createUnmarshaller();
            final Facility facility = unmarshaller.unmarshal(xmlStreamReader, Facility.class).getValue();
            System.out.println(facility.toString());

            Marshaller marshaller = JAXBContext.newInstance(Facility.class).createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.TRUE);
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
            marshaller.marshal(facility, System.out);
            
            
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
}

通过上面的代码，我得到了除上面PropertyCatalist之外的所有元素。下面是输出

Answer 1

我发现您的代码存在一些问题：

>

您已经在java类中添加了多个根元素（ArrangementActive，Property tyData）。应该只有一个根元素（设施）。

您在proporter中添加了几个属性，您应该包括所有属性，除非其中任何属性被标记为瞬态。

您的XML将字段大写为，但字段是小写的，因此它不能在解组期间直接赋值。您可以使用@XmlElement来指定它在XML中的名称。

（您要求的）您必须在列表中使用@xmlementwrapper和xmlement。

注意：我使用了Project Lombok Getter

下面是解组和封送XML的代码：

Facility.class

@XmlRootElement(name = "FACILITY")
@Data
@NoArgsConstructor
@XmlAccessorType(XmlAccessType.FIELD)
public class Facility {

    @XmlElement(name = "ARRANGEMENTACTIVITY")
    private ArrangementActivity arrangementActivity;
}

安排活动。班

@XmlAccessorType(XmlAccessType.NONE)
@XmlType(propOrder = {"id", "customer","propertyDataList","application","version","operation"})
@Data
public class ArrangementActivity {

    @XmlElement(name = "APPLICATION")
    private String application;

    @XmlElement(name = "VERSION")
    private String version;

    @XmlElement(name = "OPERATION")
    private String operation;

    @XmlElement(name = "ID")
    private String id;

    @XmlElement(name = "CUSTOMER")
    private String customer;

    @XmlElementWrapper(name = "PROPERTYDATALIST")
    @XmlElement(name = "PROPERTYDATA")
    private List<PropertyData> propertyDataList;
}

属性数据。类别：

@XmlAccessorType(XmlAccessType.NONE)
@Data
@XmlType(propOrder = {"property", "amount", "term", "maturityDate", "fixedRate" })
public class PropertyData {

    @XmlElement(name = "PROPERTY")
    private String property;

    @XmlElement(name = "AMOUNT")
    private String amount;

    @XmlElement(name = "TERM")
    private String term;

    @XmlElement(name = "MATURITYDATE")
    private String maturityDate;

    @XmlElement(name = "FIXEDRATE")
    private String fixedRate;
}

JaxbExampleMain。类别：

public class JaxbExampleMain {
    public static void main(String[] args) throws JAXBException, XMLStreamException {
        final InputStream inputStream = Unmarshalling.class.getClassLoader().getResourceAsStream("facility.xml");
        final XMLStreamReader xmlStreamReader = XMLInputFactory.newInstance().createXMLStreamReader(inputStream);
        final Unmarshaller unmarshaller = JAXBContext.newInstance(Facility.class).createUnmarshaller();
        final Facility facility = unmarshaller.unmarshal(xmlStreamReader, Facility.class).getValue();
        System.out.println(facility.toString());

        Marshaller marshaller = JAXBContext.newInstance(Facility.class).createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.TRUE);
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
        marshaller.marshal(facility, System.out);
    }
}

以下是您得到的输出：

Facility(arrangementActivity=ArrangementActivity(application=null, version=null, operation=null, id=NEW, customer=500000030, propertyDataList=[PropertyData(property=FACOMMITMENT, amount=600000, term=5Y, maturityDate=20261001, fixedRate=null), PropertyData(property=PRINCIPALINT, amount=null, term=null, maturityDate=null, fixedRate=3.5)]))
<FACILITY>
   <ARRANGEMENTACTIVITY>
      <ID>NEW</ID>
      <CUSTOMER>500000030</CUSTOMER>
      <PROPERTYDATALIST>
         <PROPERTYDATA>
            <PROPERTY>FACOMMITMENT</PROPERTY>
            <AMOUNT>600000</AMOUNT>
            <TERM>5Y</TERM>
            <MATURITYDATE>20261001</MATURITYDATE>
         </PROPERTYDATA>
         <PROPERTYDATA>
            <PROPERTY>PRINCIPALINT</PROPERTY>
            <FIXEDRATE>3.5</FIXEDRATE>
         </PROPERTYDATA>
      </PROPERTYDATALIST>
   </ARRANGEMENTACTIVITY>
</FACILITY>