杰克逊反序列化枚举值

Question

Can i set default value for enum, when i am passing null value?

public enum Something {
@JsonEnumDefaultValue
A(new BigDecimal(123)),
B(new BigDecimal(555)),
C(new BigDecimal(21312));

private BigDecimal value;

Something(BigDecimal value) {
    this.value = value;
}

public BigDecimal getValue() {
    return value;
}

}

I have this enum as field in my DTO, when i pass null value - jackon deserializes it as null, but when i pass something weird - it sets default value. My jackson config is here:

@Bean
public ObjectMapper mapper() {
    val mapper = new ObjectMapper();
    return mapper.enable(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_USING_DEFAULT_VALUE);
}

Dto class:

public class Dto {
private Something something;
private Smth smth;
private String name;
}

Controller:

@PostMapping
public ResponseEntity<Long> saveEntity(@RequestBody Dto dto) {
    return ResponseEntity.ok(repository.save(
            MyEntity.builder()
                    .name(dto.getName())
                    .something(dto.getSomething())
                    .smth(dto.getSmth())
                    .build())
            .getId());
}

Answer 1

You need to provide default value at class level, then it will work for null values.

Eg:

class Dto {
    private Something something = Something.A;
    private Smth smth;
    private String name;
}