[FIXED] Customise JSON date formatting of JSON for spring-mvc (non-boot)?

Issue

I am converting my app to get rid of spring-boot, it now uses only Spring (5.3).

I've added the @EnableWebMvc configuration and I have my endpoints working properly for the most part - they return the data I want as JSON.

Previously, I customised the date format with the spring-boot property: spring.jackson.date-format=yyyy-MM-dd'T'HH:mm:ss.SSS'Z'

In the new pure-spring app though, it's regressed back serializing to a long value.

I've tried the following, but it doesn't seem to even use these beans at all:

  @Bean
  public ObjectMapper objectMapper() {
    DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
    ObjectMapper dateFormatMapper = new ObjectMapper();
    dateFormatMapper.setDateFormat(dateFormat);
    return dateFormatMapper;
  }

  @Bean 
  public MappingJackson2HttpMessageConverter mappingJackson2JsonView(){
    var converter = new MappingJackson2HttpMessageConverter();
    converter.getObjectMapper().setDateFormat(
      new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'") );
    return converter;    
  }

I'm looking to customise the format globally, not on a per-field basis.

What would be the equivalent of spring.jackson.date-format for pure Spring @EnableWebMvc setup?

Solution

You can customize MappingJackson2HttpMessageConverter by using WebMvcConfigurer with @EnableWebMvc.

For example:

@Configuration
@EnableWebMvc
public class YourConfiguration implements WebMvcConfigurer {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder()
                .indentOutput(true)
                .dateFormat(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"));
        converters.add(new MappingJackson2HttpMessageConverter(builder.build()));
    }
}

For more information, please see 1.11.7. Message Converters - Web on Servlet Stack - docs.spring.io.

Answered By - Tomoki Sato
Answer Checked By - Marilyn (JavaFixing Volunteer)