Get Jackson XMLMapper to read root element name

Question

How do I get Jackson's XMLMapper to read the name of the root xml element when deserializing?

I am deserializing input XML to generic Java class, LinkedHashMap and then to JSON. I want to dynamically read the root element of input XML on deserialization to LinkedHashMap.

Code

XmlMapper xmlMapper = new XmlMapper();
Map entries = xmlMapper.readValue(new File("source.xml"), LinkedHashMap.class);
ObjectMapper jsonMapper = new ObjectMapper();
String json = jsonMapper.writer().writeValueAsString(entries);
System.out.println(json);

Input XML

<?xml version="1.0" encoding="ISO-8859-1"?>
<File>
  <NumLeases>1</NumLeases>
  <NEDOCO>18738</NEDOCO>
  <NWUNIT>0004</NWUNIT>
  <FLAG>SUCCESS</FLAG>
  <MESSAGE>Test Upload</MESSAGE>
  <Lease>
     <LeaseVersion>1</LeaseVersion>
     <F1501B>
        <NEDOCO>18738</NEDOCO>
        <NWUNIT>0004</NWUNIT>
        <NTRUSTRECORDKEY>12</NTRUSTRECORDKEY>
     </F1501B>
  </Lease>
</File>

Actual Output

{"NumLeases":"1","NEDOCO":"18738","NWUNIT":"0004","FLAG":"SUCCESS","MESSAGE":"Test Upload","Lease":{"LeaseVersion":"1","F1501B":{"NEDOCO":"18738","NWUNIT":"0004","NTRUSTRECORDKEY":"12"}}}  

Expected Output (Note: There is a root element named "File" present in JSON)

{"File":{"NumLeases":"1","NEDOCO":"18738","NWUNIT":"0004","FLAG":"SUCCESS","MESSAGE":"Test Upload","Lease":{"LeaseVersion":"1","F1501B":{"NEDOCO":"18738","NWUNIT":"0004","NTRUSTRECORDKEY":"12"}}}}

There's probably some switch somewhere to set it. Any help shall be appreciated.

Answer 1

Sadly there is no flag for that. It can be done with a custom implementation of com.fasterxml.jackson.databind.deser.std.JsonNodeDeserializer. (Jackson How-To: Custom Deserializers):

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.deser.std.JsonNodeDeserializer;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import com.fasterxml.jackson.dataformat.xml.deser.FromXmlParser;
import java.io.File;
import java.io.IOException;
//...
XmlMapper xmlMapper = new XmlMapper();
xmlMapper.registerModule(new SimpleModule().addDeserializer(JsonNode.class, 

    new JsonNodeDeserializer() {

        @Override
        public JsonNode deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
            String rootName = ((FromXmlParser)p).getStaxReader().getLocalName();
            return ctxt.getNodeFactory()
                    .objectNode().set(rootName, super.deserialize(p, ctxt));
        }
    }));

JsonNode entries = xmlMapper.readTree(new File("source.xml"));
System.out.println(entries);