Deserialize enum ignoring case in Spring Boot controller

import com.fasterxml.jackson.annotation.JsonCreator;
import java.util.Arrays;
import java.util.Optional;

public enum ExampleEnum {
    FIRST,
    SECOND;

    @JsonCreator
    public static ExampleEnum setValue(String key) {
        return Arrays.stream(ExampleEnum.values())
            .filter(exampleEnum -> exampleEnum.toString().equals(key.toUpperCase()))
            .findAny()
            .orElse(null);
}

EDIT: The answer below is incorrect. You have to define a custom PropertyEditor and register it with Spring @InitBinder which I explained in this post. Thanks to @Dave for pointing this out in the comments.

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Spring Boot 2.0 is using Jackson 2.9 which has ACCEPT_CASE_INSENSITIVE_ENUMS feature. You should be able to enable it by setting

spring.jackson.mapper.ACCEPT_CASE_INSENSITIVE_ENUMS = true 

property as per docs, Appendix A.