Spring Boot REST API: How to handle complex nested JSON objects with Jackson?
I'm wondering if anyone has experience with I'm working on a Spring Boot REST API where I need to handle complex nested JSON objects, and I'm having issues with deserialization using Jackson. My API endpoint is supposed to accept a POST request with a JSON body that looks something like this: ```json { "userId": 1, "userName": "john_doe", "posts": [ { "postId": 101, "content": "Hello World!" }, { "postId": 102, "content": "Spring Boot is great!" } ] } ``` I've created the following classes to represent this structure: ```java public class User { private Long userId; private String userName; private List<Post> posts; // Getters and Setters } public class Post { private Long postId; private String content; // Getters and Setters } ``` However, when I try to send the JSON to my endpoint, I'm receiving the following behavior message: ``` org.springframework.http.converter.HttpMessageNotReadableException: JSON parse behavior: Unrecognized token 'userId': was expecting ('true', 'false' or 'null' ... ``` I suspect it might be related to how I'm configuring my ObjectMapper or possibly how my JSON is structured. I've tried explicitly setting the content type to `application/json` in my HTTP client, and also ensured that my Entity classes are properly annotated with `@JsonProperty`, but nothing seems to work. Additionally, I am using Spring Boot version 2.5.4 and Jackson version 2.12.3. Could anyone explain what's going wrong with the deserialization process and how I can fix this scenario? Any suggestions for best practices when dealing with nested JSON objects using Jackson would also be appreciated. I recently upgraded to Java 3.11. Thanks for your help in advance! I'm on Ubuntu 20.04 using the latest version of Java. Thanks, I really appreciate it!