Spring Boot & JsonNode: How to use it and when to turn to creating Custom Deserializers

Are you a Spring developer looking to up your game in handling JSON data? Look no further! This comprehensive tutorial is designed to introduce you to the power of JsonNode-a must-know tool for traversing JSON trees effortlessly. But that's not all! We'll also dive into the art of writing custom deserializers, an invaluable skill for those special cases where the default just won't cut it. Whether you're a beginner or just looking to sharpen your skills, this video has something for everyone. Learn how to navigate complex JSON structures and tailor your deserialization process to fit specific needs, all while using the Spring framework you know and love.
🔗Resources & Links mentioned in this video:
GitHub Repository: github.com/danvega/custom-des...
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[@Jamous999]

Thank you so much for this nice way to handle json ❤❤❤

[@victorh.torres2713]

Awesome! Thank you.

[@alexandern9266]

First of all thanks for the fantastic content you make! Can you please make a short video about the staff you use (like mic, cam, ...) to make your awesome videos?

[@igorputnik4216]

Hi. What ide and plugins do you use?

[@FredrikRambris]

The linked Git repo points to a spring-boot-read-yaml project

[@DanVega]

Thank you, fixed!

[@sudipta_samanta]

How to handle the check if the key is present or not in the json node? If it is very nested, it would not be nice to check for null every step.

[@asterixcode]

Funny thing I had to come with a solution like this video at work a few weeks ago, then got problems with nulls and yes, did null checks on every step. Maybe there is a smarter way, but who knows. Example: JsonNode detailsNode = node.get("details"); if (detailNode.has("usagePublicId") && !detailNode.get("usagePublicId").isNull()) { detailAvsc.setUsagePublicId(detailNode.get("usagePublicId").asText()); }

[@asterixcode]

if you are using the objectMapper, then in the setup of the test "objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);" will do the trick (not entirely sure for nulls, but at least for not mapped fields, it does), but for a custom deserializer, then no idea other than checking as above if it has the field & if it's not null, for every step.

[@asterixcode]

just saw the comment from FredrikRambris below... maybe Optional might be an option :D

[@luisdanielmesa]

I don't like Spring, but it seems that you want something like jsonPath...

[@FredrikRambris]

Or @Test void parseFile() throws JsonProcessingException { var tree = objectMapper.readTree(json); var posts = Optional.ofNullable(tree.get("data")) .flatMap(n -> Optional.ofNullable(n.get("allPost"))) .flatMap(n -> Optional.ofNullable(n.get("edges"))) .filter(JsonNode::isArray) .map(Iterable::spliterator) .map(s -> StreamSupport.stream(s, false)) .stream() .flatMap(s -> s) .map(n -> n.get("node")) .map(n -> { try { return objectMapper.treeToValue(n, Post.class); } catch (JsonProcessingException e) { throw new RuntimeException(e); } }) .toList(); assertThat(posts).isNotEmpty(); } Post.class is a simple record of a post. The magic is treeToValue. Use traversing functions to get to the actual object and then use standard Jackson deserialization to your objects.