Jackson UnrecognizedProperyException when parsing XML

Question

I am trying to parse an XML where I generate the DTOs using maven-jaxb2-plugin from xsd file. But I get this exception and don't know why, everything seems alright.

Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "Publish_Date" (class com.compnay.package.SdnList$PublshInformation), not marked as ignorable (2 known properties: "publishDate", "recordCount"])
 at [Source: (PushbackInputStream); line: 4, column: 44] (through reference chain: com.compnay.package.SdnList["publshInformation"]->com.compnay.package.domain.SdnList$PublshInformation["Publish_Date"])

Jaxb execution for the relevant xsd

<execution>
  <id>tds</id>
  <goals>
    <goal>generate</goal>
  </goals>
  <configuration>
    <schemas>
      <schema>                              
        <url>xsd url</url>
      </schema>
  </schemas>                     
  <generatePackage>com.company.domain</generatePackage>
  <generateDirectory>${project.basedir}/domain/src/main/java</generateDirectory>
  <episode>false</episode>
  </configuration>
</execution>

Part of the XML file where I get the error.

<publshInformation>
  <Publish_Date>08/06/2021</Publish_Date>
  <Record_Count>9030</Record_Count>
</publshInformation>

Rest template Configuration

JacksonXmlModule module = new JacksonXmlModule();
module.setDefaultUseWrapper(false);

final XmlMapper xmlMapper = new XmlMapper(module);
xmlMapper.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true);
// xmlMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); // Works when this is on

final MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter(xmlMapper);
        converter.setSupportedMediaTypes(Collections.singletonList(MediaType.APPLICATION_XML));

        return new RestTemplateBuilder()
                .setReadTimeout(Duration.ofMillis(readTimeout))
                .setConnectTimeout(Duration.ofMillis(connectTimeout))
                .messageConverters(converter)
                .build();

Part of a Generated DTO

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
    "publshInformation",
    "sdnEntry"
})
@XmlRootElement(name = "sdnList")
public class SdnList {

    @XmlElement(required = true)
    protected SdnList.PublshInformation publshInformation;
    @XmlElement(required = true)
    protected List<SdnList.SdnEntry> sdnEntry;

    ........

    /**
     * <p>Java class for anonymous complex type.
     * 
     * <p>The following schema fragment specifies the expected content contained within this class.
     * 
     * <pre>
     * &lt;complexType&gt;
     *   &lt;complexContent&gt;
     *     &lt;restriction base="{http://www.w3.org/2001/XMLSchema}anyType"&gt;
     *       &lt;sequence&gt;
     *         &lt;element name="Publish_Date" type="{http://www.w3.org/2001/XMLSchema}string" minOccurs="0"/&gt;
     *         &lt;element name="Record_Count" type="{http://www.w3.org/2001/XMLSchema}int" minOccurs="0"/&gt;
     *       &lt;/sequence&gt;
     *     &lt;/restriction&gt;
     *   &lt;/complexContent&gt;
     * &lt;/complexType&gt;
     * </pre>
     * 
     * 
     */
    @XmlAccessorType(XmlAccessType.FIELD)
    @XmlType(name = "", propOrder = {
        "publishDate",
        "recordCount"
    })
    public static class PublshInformation {

        @XmlElement(name = "Publish_Date")
        protected String publishDate;
        @XmlElement(name = "Record_Count")
        protected Integer recordCount;
        ........
    }
}

I can make it work with using xmlMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false) but I don't want to lose other data. Can anyone help me figure it out why I get unrecognizedPropertyException? I will appreciate any pointers.

Answer 1

I guess you are doing something before the derealization which is making your input stream empty due to which you are getting this error. I used the provided XML and seems to work fine for me:

XML:

<publshInformation>
    <Publish_Date>08/06/2021</Publish_Date>
    <Record_Count>9030</Record_Count>
</publshInformation>

PublshInformation.class:

@XmlRootElement(name = "publshInformation")
@Data
@XmlAccessorType(XmlAccessType.FIELD)
public class PublshInformation {

    @XmlElement(name = "Publish_Date")
    private String Publish_Date;

    @XmlElement(name = "Record_Count")
    private Integer recordCount;

}

PublishMain.class:

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

        Marshaller marshaller = JAXBContext.newInstance(PublshInformation.class).createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.TRUE);
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
        marshaller.marshal(publshInformation, System.out);*/

        System.out.println(inputStream);
        final XmlMapper xmlMapper = new XmlMapper();
        xmlMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        PublshInformation jacksonPublish = xmlMapper.readValue(xmlStreamReader, PublshInformation.class);
        System.out.println(jacksonPublish);

        xmlMapper.writerWithDefaultPrettyPrinter().writeValue(System.out, jacksonPublish);

    }
}

This would produce the result:

java.io.BufferedInputStream@73a28541
PublshInformation(Publish_Date=null, recordCount=null)
<PublshInformation>
  <recordCount/>
  <publish_Date/>
</PublshInformation>

The above code works even by using the pure JAXB. If you uncomment then it will do it using the JAXB. I used the latest jackson-dataformat-xml 2.12.4

1. Make your fields private.
2. Use the latest version of the Jackson
3. Ensure your input is not being used before which may become empty.

This should work I believe.