JSON Java 8 LocalDateTime format in Spring Boot

update: Spring Boot 2.x doesn't require this configuration anymore. I've written a more up to date answer here.

(This is the way of doing it before Spring Boot 2.x, it might be useful for people working on an older version of Spring Boot)

I finally found here how to do it. To fix it, I needed another dependency:

compile("com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.4.0")

By including this dependency, Spring will automatically register a converter for it, as described here. After that, you need to add the following to application.properties:

spring.jackson.serialization.write_dates_as_timestamps=false

This will ensure that a correct converter is used, and dates will be printed in the format of 2016-03-16T13:56:39.492

Annotations are only needed in case you want to change the date format.

I added the com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.6.1 dependency and started to get the date in the following format:

"birthDate": [
    2016,
    1,
    25,
    21,
    34,
    55
  ]

which is not what I wanted but I was getting closer. I then added the following

spring.jackson.serialization.write_dates_as_timestamps=false

to application.properties file which gave me the correct format that I needed.

"birthDate": "2016-01-25T21:34:55"

Here it is in maven, with the property so you can survive between spring boot upgrades

<dependency>
        <groupId>com.fasterxml.jackson.datatype</groupId>
        <artifactId>jackson-datatype-jsr310</artifactId>
        <version>${jackson.version}</version>
</dependency>

1) Dependency

 compile group: 'com.fasterxml.jackson.datatype', name: 'jackson-datatype-jsr310', version: '2.8.8' 

2) Annotation with date-time format.

public class RestObject {

    private LocalDateTime timestamp;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    public LocalDateTime getTimestamp() {
        return timestamp;
    }
}

3) Spring Config.

@Configuration
public class JacksonConfig {

    @Bean
    @Primary
    public ObjectMapper objectMapper(Jackson2ObjectMapperBuilder builder) {
        System.out.println("Config is starting.");
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        return objectMapper;
    }
}

Writing this answer as a reminder for me as well.

I combined several answers here and in the end mine worked with something like these. (I am using SpringBoot 1.5.7 and Lombok 1.16.16)

@Data
public Class someClass {

   @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME)
   @JsonSerialize(using = LocalDateTimeSerializer.class)
   @JsonDeserialize(using = LocalDateTimeDeserializer.class)
   private LocalDateTime someDate;

}