Jackson serializes a ZonedDateTime wrongly in Spring Boot

Question

I have a simple application with Spring Boot and Jetty. I have a simple controller returning an object which has a Java 8 ZonedDateTime:

public clas         


        

Answer 1

If you either don't rely on SpringBoot's auto-configuration feature - you don't provide spring.jackson.serialization.WRITE_DATES_AS_TIMESTAMPS = false property into your configuration file - or for whatever reason you create ObjectMapper instance manually. You can disable this feature programatically as follows:

ObjectMapper m = new ObjectMapper();
m.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

this is for jackson 2.8.7

Answer 2

For Jackson 2.10 and above,

parent pom.xml

<!-- https://github.com/FasterXML/jackson-bom -->
<dependencyManagement>
  <dependency>
    <groupId>com.fasterxml.jackson</groupId>
    <artifactId>jackson-bom</artifactId>
    <version>2.10.3</version>
    <type>pom</type>
    <scope>import</scope>
  </dependency>
</dependencyManagement>

module pom.xml

<!-- https://github.com/FasterXML/jackson-modules-java8 -->
<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

JsonMapper creation, possibly in your @Configuration class

@Bean
public JsonMapper jsonMapper() {
    return JsonMapper.builder()
        .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
        .addModule(new JavaTimeModule())
        .build();
}

Further reading:

• What's new in Jackson 2.10
• Use JsonMapper instead of ObjectMapper
• Use Builder pattern

Answer 3

There is a library jackson-datatype-jsr310. Try it.

This library covers new datetime API and includes serializers for ZonedDateTime too.

All you need is just to add JavaTimeModule:

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JavaTimeModule());

UPDATE

To convert datetime to ISO-8601 string you should disable WRITE_DATES_AS_TIMESTAMPS feature. You can easily do by either overriding ObjectMapper bean or by using application properties:

spring.jackson.serialization.WRITE_DATES_AS_TIMESTAMPS = false

Answer 4

The answer was already mentioned above but I think it's missing some info. For those looking to parse Java 8 timestamps in many forms (not just ZonedDateTime). You need a recent version of jackson-datatype-jsr310 in your POM and have the following module registered:

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

To test this code

@Test
void testSeliarization() throws IOException {
    String expectedJson = "{\"parseDate\":\"2018-12-04T18:47:38.927Z\"}";
    MyPojo pojo = new MyPojo(ZonedDateTime.parse("2018-12-04T18:47:38.927Z"));

    // serialization
    assertThat(objectMapper.writeValueAsString(pojo)).isEqualTo(expectedJson);

    // deserialization
    assertThat(objectMapper.readValue(expectedJson, MyPojo.class)).isEqualTo(pojo);
}

Note that you can configure your object mapper globally in Spring or dropwizard to achieve this. I have not yet found a clean way to do this as an annotation on a field without registering a custom (de)serializer.