[java] Java 8 LocalDate Jackson format

For java.util.Date when I do

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

then in JSON request when I send

{ {"dateOfBirth":"01/01/2000"} }  

it works.

How should I do this for Java 8's LocalDate field??

I tried having

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

It didn't work.

Can someone please let me know what's the right way to do this..

Below are dependencies

<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>jaxrs-api</artifactId>
     <version>3.0.9.Final</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.jaxrs</groupId>
    <artifactId>jackson-jaxrs-json-provider</artifactId>
    <version>2.4.2</version>
</dependency>
<dependency>
    <groupId>com.wordnik</groupId>
    <artifactId>swagger-annotations</artifactId>
    <version>1.3.10</version>
</dependency>

The simplest solution (which supports deserialization and serialization as well) is

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;

@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy")
@JsonDeserialize(using = LocalDateDeserializer.class)
@JsonSerialize(using = LocalDateSerializer.class)
private LocalDate dateOfBirth;

While using the following dependencies in your project.

Maven

<dependency>
   <groupId>com.fasterxml.jackson.core</groupId>
   <artifactId>jackson-databind</artifactId>
   <version>2.9.7</version>
</dependency>
<dependency>
   <groupId>com.fasterxml.jackson.datatype</groupId>
   <artifactId>jackson-datatype-jsr310</artifactId>
   <version>2.9.7</version>
</dependency>

Gradle

compile "com.fasterxml.jackson.core:jackson-databind:2.9.7"
compile "com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.9.7"

No additional implementation of a ContextResolver, Serializer or Deserializer is required.

As of 2020 and Jackson 2.10.1 there's no need for any special code, it's just a matter of telling Jackson what you want:

ObjectMapper objectMapper = new ObjectMapper();

// Register module that knows how to serialize java.time objects
// Provided by jackson-datatype-jsr310
objectMapper.registerModule(new JavaTimeModule());

// Ask Jackson to serialize dates as String (ISO-8601 by default)
objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

This has already been mentioned in this answer, I'm adding a unit test verifying the functionality:

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import lombok.Data;
import org.junit.jupiter.api.Test;

import java.time.LocalDate;

import static org.junit.jupiter.api.Assertions.assertEquals;

public class LocalDateSerializationTest {

    @Data
    static class TestBean {
        // Accept default ISO-8601 format
        LocalDate birthDate;
        // Use custom format
        @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy")
        LocalDate birthDateWithCustomFormat;
    }

    @Test
    void serializeDeserializeTest() throws JsonProcessingException {
        ObjectMapper objectMapper = new ObjectMapper();

        // Register module that knows how to serialize java.time objects
        objectMapper.registerModule(new JavaTimeModule());

        // Ask Jackson to serialize dates as String (ISO-8601 by default)
        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

        // The JSON string after serialization
        String json = "{\"birthDate\":\"2000-01-02\",\"birthDateWithCustomFormat\":\"03/02/2001\"}";

        // The object after deserialization
        TestBean object = new TestBean();
        object.setBirthDate(LocalDate.of(2000, 1, 2));
        object.setBirthDateWithCustomFormat(LocalDate.of(2001, 2, 3));

        // Assert serialization
        assertEquals(json, objectMapper.writeValueAsString(object));

        // Assert deserialization
        assertEquals(object, objectMapper.readValue(json, TestBean.class));
    }
}

TestBean uses Lombok to generate the boilerplate for the bean.

Just an update of Christopher answer.

Since the version 2.6.0

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
    <version>2.9.0</version>
</dependency>

Use the JavaTimeModule instead of JSR310Module (deprecated).

@Provider
public class ObjectMapperContextResolver implements ContextResolver<ObjectMapper> {  
    private final ObjectMapper MAPPER;

    public ObjectMapperContextResolver() {
        MAPPER = new ObjectMapper();
        MAPPER.registerModule(new JavaTimeModule());
        MAPPER.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
    }

    @Override
    public ObjectMapper getContext(Class<?> type) {
        return MAPPER;
    }  
}

According to the documentation, the new JavaTimeModule uses same standard settings to default to serialization that does NOT use Timezone Ids, and instead only uses ISO-8601 compliant Timezone offsets.

Behavior may be changed using SerializationFeature.WRITE_DATES_WITH_ZONE_ID

In Spring Boot web app, with Jackson and JSR 310 version "2.8.5"

compile "com.fasterxml.jackson.core:jackson-databind:2.8.5"
runtime "com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.8.5"

The @JsonFormat works:

import com.fasterxml.jackson.annotation.JsonFormat;

@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
private LocalDate birthDate;

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);
        }
    }
}

Simplest and shortest so far:

@JsonFormat(pattern = "yyyy-MM-dd")
private LocalDate localDate;

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private LocalDateTime localDateTime;

no dependency required with Spring boot >= 2.2+

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.

https://stackoverflow.com/a/53251526/1282532 is the simplest way to serialize/deserialize property. I have two concerns regarding this approach - up to some point violation of DRY principle and high coupling between pojo and mapper.

public class Trade {
    @JsonFormat(pattern = "yyyyMMdd")
    @JsonDeserialize(using = LocalDateDeserializer.class)
    @JsonSerialize(using = LocalDateSerializer.class)
    private LocalDate tradeDate;
    @JsonFormat(pattern = "yyyyMMdd")
    @JsonDeserialize(using = LocalDateDeserializer.class)
    @JsonSerialize(using = LocalDateSerializer.class)
    private LocalDate maturityDate;
    @JsonFormat(pattern = "yyyyMMdd")
    @JsonDeserialize(using = LocalDateDeserializer.class)
    @JsonSerialize(using = LocalDateSerializer.class)
    private LocalDate entryDate;
}

In case you have POJO with multiple LocalDate fields it's better to configure mapper instead of POJO. It can be as simple as https://stackoverflow.com/a/35062824/1282532 if you are using ISO-8601 values ("2019-01-31")

In case you need to handle custom format the code will be like this:

ObjectMapper mapper = new ObjectMapper();
JavaTimeModule javaTimeModule = new JavaTimeModule();
javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyyMMdd")));
javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyyMMdd")));
mapper.registerModule(javaTimeModule);

The logic is written just once, it can be reused for multiple POJO

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

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;

@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));
    }
}

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JavaTimeModule());
mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);

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.

annotation in Pojo without using additional dependencies

@DateTimeFormat (pattern = "yyyy/MM/dd", iso = DateTimeFormat.ISO.DATE)
private LocalDate enddate;