👀 Views: 0 💬 Answers: 1 📅 Created: 2025-08-22

java jackson json deserialization Java

I'm testing a new approach and I'm performance testing and I'm working on a project where I need to deserialize JSON data into Java objects using Jackson. The JSON keys are in mixed case (e.g., `firstName`, `lastName`, `emailAddress`), but my Java class fields are in camel case (e.g., `first_name`, `last_name`, `email_address`). I expected Jackson to handle the naming convention automatically with its default settings, but it seems to be treating the keys as case-sensitive. Consequently, I am getting null values for the fields during the deserialization process. Here's a simplified version of my code: ```java import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.PropertyNamingStrategy; public class User { private String first_name; private String last_name; private String email_address; // Getters and setters omitted for brevity } public class JsonDeserializer { public static void main(String[] args) { String json = "{\"firstName\": \"John\", \"lastName\": \"Doe\", \"emailAddress\": \"john.doe@example.com\"}"; ObjectMapper objectMapper = new ObjectMapper(); objectMapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE); try { User user = objectMapper.readValue(json, User.class); System.out.println(user); } catch (Exception e) { e.printStackTrace(); } } } ``` However, when I run this, I get a `null` result for all fields in the `User` object. I also tried annotating my fields with `@JsonProperty`, but that didn't seem to resolve the issue either. Can anyone suggest the right approach to handle this mixed case key scenario in Jackson? Any help would be greatly appreciated! How would you solve this? I'm on Ubuntu 22.04 using the latest version of Java.