json-mapper | Map one object | JSON Processing library

There are several possible approaches to solve this issue and some of them are clearly explained here: https://www.baeldung.com/spring-boot-customize-jackson-objectmapper

Generally you can:

1. Override default ObjectMapper by creating custom ObjectMapper bean and marking it as @Primary (the simplest way but heavily impacts your application as all ObjectMapper instances you inject in code will use this one by default which may be good or not for you)

2. Define custom bean for Jackson2ObjectMapperBuilder and set proper serializationInclusion on this builder.

3. Register custom HTTP message converter in Spring which will use custom ObjectMapper by defining bean for MappingJackson2HttpMessageConverter (constructor of this converter accepts ObjectMapper so you can pass properly configured mapper there)

• Firstly, the json shared in the question is not a valid json. Remove , after "endDatetime": null
• Add @NoArgsConstructor annotation to your DataDto class.
• Register ObjectMapper to disable serialization/deserialization of Instant as timestamp, which it does by default.

Sample code which works for me. I know you are doing via the client but I think this should help you. Either pass a custom object mapper to the client when creating or get the JSON as a string and convert manually.

Your code works, I prepared another example to show here. I excluded jackson like below just to make sure it is not used.

From your error msg:

Expected BEGIN_OBJECT but was STRING at line 1 column 12 path $.someId

And your Object SomeGetRequest doesn't have String type someId.

Convert error may be because you passing a string for `someId, but in the class, it's an object (ObjectId), Could you just change ObjectId -> String, and try it again.

You are not supposed to use Mono in controllers, as such it doesn't appear to be mapped correctly by any serializer.

There are two alternatives

1. Use response entity

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Also, please turn on less secure app access in your account.

Try to make the response object old-school. Create new array list, create new User, set its id, set its name, add it to the list and return the list