Java 8 LocalDate Jackson format

Question

For java.util.Date when I do

@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = \"dd/MM/yyyy\")  
  private Date dateOfBirth;
<         


        

Answer 1

In configuration class define LocalDateSerializer and LocalDateDeserializer class and register them to ObjectMapper via JavaTimeModule like below:

@Configuration
public class AppConfig
{
@Bean
    public ObjectMapper objectMapper()
    {
        ObjectMapper mapper = new ObjectMapper();
        mapper.setSerializationInclusion(Include.NON_EMPTY);
        //other mapper configs
        // Customize de-serialization


        JavaTimeModule javaTimeModule = new JavaTimeModule();
        javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer());
        javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer());
        mapper.registerModule(javaTimeModule);

        return mapper;
    }

    public class LocalDateSerializer extends JsonSerializer<LocalDate> {
        @Override
        public void serialize(LocalDate value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
            gen.writeString(value.format(Constant.DATE_TIME_FORMATTER));
        }
    }

    public class LocalDateDeserializer extends JsonDeserializer<LocalDate> {

        @Override
        public LocalDate deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
            return LocalDate.parse(p.getValueAsString(), Constant.DATE_TIME_FORMATTER);
        }
    }
}

Answer 2

@JsonSerialize and @JsonDeserialize worked fine for me. They eliminate the need to import the additional jsr310 module:

@JsonDeserialize(using = LocalDateDeserializer.class)  
@JsonSerialize(using = LocalDateSerializer.class)  
private LocalDate dateOfBirth;

Deserializer:

public class LocalDateDeserializer extends StdDeserializer<LocalDate> {

    private static final long serialVersionUID = 1L;

    protected LocalDateDeserializer() {
        super(LocalDate.class);
    }


    @Override
    public LocalDate deserialize(JsonParser jp, DeserializationContext ctxt)
            throws IOException, JsonProcessingException {
        return LocalDate.parse(jp.readValueAs(String.class));
    }

}

Serializer:

public class LocalDateSerializer extends StdSerializer<LocalDate> {

    private static final long serialVersionUID = 1L;

    public LocalDateSerializer(){
        super(LocalDate.class);
    }

    @Override
    public void serialize(LocalDate value, JsonGenerator gen, SerializerProvider sp) throws IOException, JsonProcessingException {
        gen.writeString(value.format(DateTimeFormatter.ISO_LOCAL_DATE));
    }
}

Answer 3

The following annotation worked fine for me.

No extra dependencies needed.

    @JsonProperty("created_at")
    @JsonFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss.SSSXXX")
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    private LocalDateTime createdAt;

Answer 4

If your request contains an object like this:

{
    "year": 1900,
    "month": 1,
    "day": 20
}

Then you can use:

data class DateObject(
    val day: Int,
    val month: Int,
    val year: Int
)
class LocalDateConverter : StdConverter<DateObject, LocalDate>() {
    override fun convert(value: DateObject): LocalDate {
        return value.run { LocalDate.of(year, month, day) }
    }
}

Above the field:

@JsonDeserialize(converter = LocalDateConverter::class)
val dateOfBirth: LocalDate

The code is in Kotlin but this would work for Java too of course.

Answer 5

Since LocalDateSerializer turns it into "[year,month,day]" (a json array) rather than "year-month-day" (a json string) by default, and since I don't want to require any special ObjectMapper setup (you can make LocalDateSerializer generate strings if you disable SerializationFeature.WRITE_DATES_AS_TIMESTAMPS but that requires additional setup to your ObjectMapper), I use the following:

imports:

import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;

code:

// generates "yyyy-MM-dd" output
@JsonSerialize(using = ToStringSerializer.class)
// handles "yyyy-MM-dd" input just fine (note: "yyyy-M-d" format will not work)
@JsonDeserialize(using = LocalDateDeserializer.class)
private LocalDate localDate;

And now I can just use new ObjectMapper() to read and write my objects without any special setup.

Answer 6

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
@JsonSerialize(using = LocalDateTimeSerializer.class)
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
private LocalDateTime createdDate;