I am using jackson-dataformat-xml (2.9) to parse an XML into JsonNode and then parse it to JSON (the XML is very dynamic so that is why I am using JsonNode instead of binding to a POJO. e.g 'elementName' and 'id' names may vary).
It happens that during the JSON parsing phase, one of the element keys is empty string ("").
XML:
<elementName>
<id type="pid">abcdef123</id>
</elementName>
Parsing logic:
public Parser() {
ObjectMapper jsonMapper = new ObjectMapper();
XmlMapper xmlMapper = new XmlMapper(new XmlFactory(new WstxInputFactory()));
}
public InputStream parseXmlResponse(InputStream xmlStream) {
InputStream stream = null;
try {
JsonNode node = xmlMapper.readTree(xmlStream);
stream = new ByteArrayInputStream(jsonMapper.writer().writeValueAsBytes(node));
} catch (IOException e) {
e.printStackTrace();
}
return stream;
}
Json:
Result:
{
"elementName": {
"id": {
"type": "pid",
"": "abcdef123"
}
},
}
Expected:
{
"elementName": {
"id": {
"type": "pid",
"value": "abcdef123"
}
},
}
My idea is to find whenever I have the empty key "" and replace it with "value". Either at XML de-serialization or during JSON serialization. I have tried to use default serializer, filter, but haven't got it working in a nice and concise way.
Suggestions are much appreciated.
Thank you for the help.
Possible Solution:
Based on @shoek suggestion I decided to write a custom serializer to avoid creating an intermediate object (ObjectNode) during the process.
edit: refactor based on the same solution proposed by @shoek.
public class CustomNode {
private JsonNode jsonNode;
public CustomNode(JsonNode jsonNode) {
this.jsonNode = jsonNode;
}
public JsonNode getJsonNode() {
return jsonNode;
}
}
public class CustomObjectsResponseSerializer extends StdSerializer<CustomNode> {
protected CustomObjectsResponseSerializer() {
super(CustomNode.class);
}
@Override
public void serialize(CustomNode node, JsonGenerator jgen, SerializerProvider provider) throws IOException {
convertObjectNode(node.getJsonNode(), jgen, provider);
}
private void convertObjectNode(JsonNode node, JsonGenerator jgen, SerializerProvider provider) throws IOException {
jgen.writeStartObject();
for (Iterator<String> it = node.fieldNames(); it.hasNext(); ) {
String childName = it.next();
JsonNode childNode = node.get(childName);
// XML parser returns an empty string as value name. Replacing it with "value"
if (Objects.equals("", childName)) {
childName = "value";
}
if (childNode instanceof ArrayNode) {
jgen.writeFieldName(childName);
convertArrayNode(childNode, jgen, provider);
} else if (childNode instanceof ObjectNode) {
jgen.writeFieldName(childName);
convertObjectNode(childNode, jgen, provider);
} else {
provider.defaultSerializeField(childName, childNode, jgen);
}
}
jgen.writeEndObject();
}
private void convertArrayNode(JsonNode node, JsonGenerator jgen, SerializerProvider provider) throws IOException {
jgen.writeStartArray();
for (Iterator<JsonNode> it = node.elements(); it.hasNext(); ) {
JsonNode childNode = it.next();
if (childNode instanceof ArrayNode) {
convertArrayNode(childNode, jgen, provider);
} else if (childNode instanceof ObjectNode) {
convertObjectNode(childNode, jgen, provider);
} else {
provider.defaultSerializeValue(childNode, jgen);
}
}
jgen.writeEndArray();
}
}
