Java 8 LocalDate Jackson 格式

Question

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>

Answer 1

I was never able to get this to work simple using annotations. To get it to work, I created a ContextResolver for ObjectMapper , then I added the JSR310Module ( update: now it is JavaTimeModule instead ), along with one more caveat, which was the need to set write-date-as-timestamp to false. See more at the documentation for the JSR310 module . Here's an example of what I used.

Dependency

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
    <version>2.4.0</version>
</dependency>

^{Note: One problem I faced with this is that the jackson-annotation version pulled in by another dependency, used version 2.3.2, which cancelled out the 2.4 required by the jsr310 . What happened was I got a NoClassDefFound for ObjectIdResolver , which is a 2.4 class. So I just needed to line up the included dependency versions}

ContextResolver

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JSR310Module;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;

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

    public ObjectMapperContextResolver() {
        MAPPER = new ObjectMapper();
        // Now you should use JavaTimeModule instead
        MAPPER.registerModule(new JSR310Module());
        MAPPER.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
    }

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

Resource class

@Path("person")
public class LocalDateResource {

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response getPerson() {
        Person person = new Person();
        person.birthDate = LocalDate.now();
        return Response.ok(person).build();
    }

    @POST
    @Consumes(MediaType.APPLICATION_JSON)
    public Response createPerson(Person person) {
        return Response.ok(
                DateTimeFormatter.ISO_DATE.format(person.birthDate)).build();
    }

    public static class Person {
        public LocalDate birthDate;
    }
}

Test

curl -v http://localhost:8080/api/person
Result: {"birthDate":"2015-03-01"}

curl -v -POST -H "Content-Type:application/json" -d "{\\"birthDate\\":\\"2015-03-01\\"}" http://localhost:8080/api/person
Result: 2015-03-01

---

See also here for JAXB solution.

UPDATE

The JSR310Module is deprecated as of version 2.7 of Jackson. Instead, you should register the module JavaTimeModule . It is still the same dependency.

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

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

Answer 4

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;

Answer 5

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.

Answer 6

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

Answer 7

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 8

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 9

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+

Answer 10

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

Answer 11

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

Answer 12

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.

Answer 13

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 14

A bit easier For Spring:

///...

@Configuration
public class ApplicationCtxBeans {
//....
    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper MAPPER = new ObjectMapper(); 
        MAPPER.registerModule(new JavaTimeModule()); // to handle LocalDateTime etc
        return MAPPER;
    }
//...
}

Usage:

@Service
public class SomeService {
    
//...
    @Autowired
    ObjectMapper jsonMapper;
//...
  JsonNode node = jsonMapper.readTree(
    jsonMapper.writeValueAsString(instance_Of_Class_With_LocalDate_Fields)
  );
//...
}

Answer 15

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 16

With spring boot 2.3.9.RELEASE,I just registered java time module with no explicit annotation in POJO class having LocalDate field & it worked.

var objectMapper = new ObjectMapper();
objectMapper.registerModule(new JavaTimeModule());

Answer 17

annotation in Pojo without using additional dependencies

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