Strange behavior when using XML attributes

My jackson version 2.8.1:

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
    <version>2.8.1</version>
</dependency>

I want to parse XML like this:

<out>
    <in>
        <first>fff</first>
        <second>sss</second>
    </in>
    <in>
        <first>fff2</first>
        <second>sss2</second>
    </in>
</out>

So my Out class:

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;

import java.util.List;

@Getter
@Setter
@ToString
@JacksonXmlRootElement(localName = "out")
@JsonIgnoreProperties(ignoreUnknown = true)
public class Out {

    @JacksonXmlProperty(localName = "in")
    @JacksonXmlElementWrapper(useWrapping = false)
    private List<In> ins;

}

In class:

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;

@Getter
@Setter
@ToString
@JsonIgnoreProperties(ignoreUnknown = true)
public class In {

    @JacksonXmlProperty(localName = "first")
    private String first;
    @JacksonXmlProperty(localName = "second")
    private String second;

}

And App class:

import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import java.io.IOException;

public class App {

    public static void main(String[] args) throws IOException {
        XmlMapper xmlMapper = new XmlMapper();
        Out out = xmlMapper.readValue(App.class.getResource("/test.xml"), Out.class);
        System.out.println(out);
    }

}

For XML above everything is good, I get Out(ins=[In(first=fff, second=sss), In(first=fff2, second=sss2)]). But I found few issues:

1. If I change Out element name to something else everything is working, is it OK?

   <bla-bla>
       <in>
           <first>fff</first>
           <second>sss</second>
       </in>
       <in>
           <first>fff2</first>
           <second>sss2</second>
       </in>
   </bla-bla>
   

   I get Out(ins=[In(first=fff, second=sss), In(first=fff2, second=sss2)])

2. Lets add some attribute to first element:

   <bla-bla>
       <in>
           <first lang="en">fff</first>
           <second>sss</second>
       </in>
   </bla-bla>
   

   And this fail with Can not construct instance of xmlparsing.In: no String-argument constructor/factory method to deserialize from String value ('sss'). More stranger that if we swap elements then everything will be good:

   <bla-bla>
       <in>
           <second>sss</second>
           <first lang="en">fff</first>
       </in>
   </bla-bla>
   

   I get Out(ins=[In(first=fff, second=sss)])

3. But this swap can’t help me for a long, because:

   <bla-bla>
       <in>
           <second>sss</second>
           <first lang="en">fff</first>
       </in>
       <in>
           <first>fff2</first>
           <second>sss2</second>
       </in>
   </bla-bla>
   

   I get only second one : Out(ins=[In(first=fff2, second=sss2)])

4. One more strange thing:

   <bla-bla>
       <in>
           <first lang="en">fff</first>
           <second></second>
       </in>
   </bla-bla>
   

   I get two elements: Out(ins=[In(first=fff, second=null), In(first=null, second=null)]). Without lang="en" everything is good.

[AnshikaKoul]

Hi @cowtowncoder ,

My jackson version 2.9.3:

<jackson.version>2.9.3</jackson.version>
<dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>${jackson.version}</version>
</dependency>
<dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>${jackson.version}</version>
</dependency>
<dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-jsr310</artifactId>
      <version>${jackson.version}</version>
</dependency>
<dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-jdk8</artifactId>
      <version>${jackson.version}</version>
</dependency>
<dependency>
      <groupId>com.fasterxml.jackson.module</groupId>
      <artifactId>jackson-module-kotlin</artifactId>
      <version>${jackson.version}</version>
</dependency>
<dependency>
      <groupId>com.fasterxml.jackson.dataformat</groupId>
      <artifactId>jackson-dataformat-xml</artifactId>
      <version>${jackson.version}</version>
</dependency>

Kotlin version : <kotlin.version>1.2.10</kotlin.version> Ratpack version : <ratpack.kotlin.version>1.1.2</ratpack.kotlin.version>

I too am facing an issue while deserialising an element with an attribute.

Example XML that needs to be parsed :

<Something>
    <first cn="abc">someValue</first>
    <second>3050</second>
</Something>          

classes that I am using :

data class Something(
   @JacksonXmlProperty(localName = "first", namespace = somenamespace)  val first: String
)

class ResponseXmlParser {
 private val xmlMapper = xmlObjectMapper()

  private val log = LoggerFactory.getLogger(javaClass)
  fun parseResponseXml(responseBodyStream: InputStream): Response {
    val jsonNode = xmlMapper.readValue(responseBodyStream, Envelope::class.java)
    log.info("RESPONSE: " + jsonNode.body.response)
    return jsonNode.body.response
  }

  private fun xmlObjectMapper(): XmlMapper {
    val jacksonXmlModule = JacksonXmlModule()
    jacksonXmlModule.setDefaultUseWrapper(false)

    return XmlMapper(jacksonXmlModule)
        .registerModule(KotlinModule())
        .registerModule(JavaTimeModule())
        .configure(DeserializationFeature.FAIL_ON_MISSING_CREATOR_PROPERTIES, false)
        .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
        .configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true) as XmlMapper
  }
}

Now in the first element that has both attribute value and textual content. whilst parsing I get this exception:

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of com.order.soap.Something (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value (‘3050’)

which is really weird. Coz I have other elements with just attribute value and all of them work just fine. Only this element which has both attribute value and textual content doesn’t work.

[yatsykve]

OK changing fields into In.class to some XmlNode like:

@Getter
@Setter
@ToString
@JsonIgnoreProperties(ignoreUnknown = true)
public class In {

    @JacksonXmlProperty(localName = "first")
    private XmlNode first;
    @JacksonXmlProperty(localName = "second")
    private XmlNode second;

}

And XmlNode.class :

@Getter
@Setter
@ToString
@JsonIgnoreProperties(ignoreUnknown = true)
public class XmlNode {

    @JacksonXmlText
    private String value;
    //still ignoring any other attributes

}

solving my problems. I’m not trying it now, because previously I have very similar issue with parsing XML (https://github.com/FasterXML/jackson-dataformat-xml/issues/191). And that time XmlNode wasn’t helpful. I think it will be something similar. But in any case thank you for answer I think we can close this issue.