I have recently explored handling JSON data with the org.json library and all went well. Now I started a bigger Maven project, for which I intend to use the Jackson libraries in stead. Sadly, it does not seem to work for me. I wanted to try out the ObjectMapper class, that VScode autocompleted for me, which a…
Tag: jackson
When is a @JsonCreator method required for parsing?
When I try to parse the following object: I get the error And I solved this by adding a creator to the User class like this: This works fine. So now I go and parse the following object: and I don’t get an error… why? why it doesn’t require me to use a constructor here? Here’s the class…
Jackson Different Deserialization vs Serlialization Method
My Spring Boot API uses camelCase, but I need to proxy some requests through my API to a 3rd party API that uses snake_case. Is it possible to configure Jackson to deserialize the 3rd party response from snake_case, then serialize it back to camelCase to my frontend? Step by step example of desired functional…
How to write common pojo deserializer for json attribute which can be an object and an array both?
Background: I am getting mismatchedInputException, when parsing json. com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type java.util.ArrayList<Data> from Object value (token JsonToken.START_OBJECT) Problem: nodes is a json-array which contains data, which can be …
Jackson serializing: Get list of processed objects
For a special case, I need to know which “source objects” of the object tree Jackson processed during serialization. I think there is some internal list, because Jackson might reuse already serialized objects if they are referenced multiple times in the object tree. Can I get this list? Or is it p…
Convert a List of JSON-objects input into a nested Map
I have a String input in the following format: Input String: [{ “id”:”1″, “name”:”A”, “address”:”St 1″},{ “id”:”2″, “name”:”B”, “address”:”St 2″}, …] And I want…
ERROR: org.codehaus.jackson.map.JsonMappingException
I’m using lombok + Java to otimizate the application. The class has the tags @Data , @EqualsAndHashCode(callSuper = false), @NoArgsConstructor, @AllArgsConstructor e @Builder before signature’s class. When I run, It shows the error below: ERROR: org.apache.cxf.jaxrs.JAXRSRuntimeException: org.code…
Deserialize json string with nested array of objects with dynamic key
Given the JSON string I need to convert it to my POJO named TransactionInfo JSON String POJO Additional Note (From comment) After the deserialization, I want to access different keys in the transactionProperties map. If it’s converted into a List<Map<String,String>> then it becomes complex. …
How to get Jackson To Throw An Error on Incorrect Casing On Deserialization
I have the following class: and my mapper looks as follows: Today, if someone messes up their json object for example messing up the capitalization on client: it will deserialize client to null. I’d like it to error because the casing is wrong. (And for any key that’s passed in with bad casing). I…
How to write output of JsonGenerator?
I’m attempting to write the output of data generated by JsonGenerator to console using : From the Java docs – https://docs.oracle.com/en/java/javase/12/docs/api/java.base/java/io/StringWriter.html: Shouldn’t the current value written to the Json generator be outputted when I use : Answer Iss…