java - Jackson overcoming underscores in favor of camel-case

Question

I retrieve a JSON string from internet; like most JSON I've seen it includes long keys that are separated by underscores. Essentially, my goal is to deserialize JSON into java-objects, but I don't use underscores in java-code.

For instance, I might have a User class with firstName field in camel-case, simultaneously I need somehow to tell Jackson to map first_name key from JSON to firstName class field. Is it possible?

class User{
    protected String firstName;
    protected String getFirstName(){return firstName;}
}

Answer 1

You can configure the ObjectMapper to convert camel case to names with an underscore:

objectMapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);

Or annotate a specific model class with this annotation:

@JsonNaming(PropertyNamingStrategy.SnakeCaseStrategy.class)

Before Jackson 2.7, the constant was named:

PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES