Master Global Date Formatting in Spring Boot: Simple Tips

Formatting dates is a frequent requirement in Java backend projects, especially when API responses contain date fields that need a specific presentation.

Using SimpleDateFormat works for individual conversions but leads to repetitive code and only affects java.util.Date types.

Spring Boot allows global date formatting via spring.jackson.date-format and spring.jackson.time-zone properties, but this configuration only applies to java.util.Date objects.

@JsonFormat Annotation

The @JsonFormat annotation can be placed on entity fields to define locale, timezone, and pattern, providing precise control over the serialization of LocalDateTime and Date fields.

@Data
public class OrderDTO {
    @JsonFormat(locale = "zh", timezone = "GMT+8", pattern = "yyyy-MM-dd")
    private LocalDateTime createTime;

    @JsonFormat(locale = "zh", timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
    private Date updateTime;
}

@JsonComponent Annotation (Recommended)

For a true global solution, define a custom component with @JsonComponent that provides serializers and deserializers for both Date and LocalDate types.

@JsonComponent
public class DateFormatConfig {
    @Value("${spring.jackson.date-format:yyyy-MM-dd HH:mm:ss}")
    private String pattern;

    @Bean
    public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilder() {
        TimeZone tz = TimeZone.getTimeZone("UTC");
        DateFormat df = new SimpleDateFormat(pattern);
        df.setTimeZone(tz);
        return builder -> builder
                .failOnEmptyBeans(false)
                .failOnUnknownProperties(false)
                .featuresToDisable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
                .dateFormat(df);
    }

    @Bean
    public LocalDateTimeSerializer localDateTimeSerializer() {
        return new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(pattern));
    }

    @Bean
    public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
        return builder -> builder.serializerByType(LocalDateTime.class, localDateTimeSerializer());
    }
}

@Configuration Annotation

An alternative global configuration uses a @Configuration class that registers a JavaTimeModule with custom serializers for LocalDateTime and deserializers for Date. Note that after applying this configuration, field‑level @JsonFormat annotations are ignored.

@Configuration
public class DateFormatConfig2 {
    @Value("${spring.jackson.date-format:yyyy-MM-dd HH:mm:ss}")
    private String pattern;

    public static DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    @Bean
    @Primary
    public ObjectMapper serializingObjectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        JavaTimeModule javaTimeModule = new JavaTimeModule();
        javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer());
        javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer());
        objectMapper.registerModule(javaTimeModule);
        return objectMapper;
    }
    // Serializer and deserializer implementations omitted for brevity
}

In summary, combining global configuration with selective @JsonFormat usage enables concise and consistent date handling across a Spring Boot application, reducing boilerplate and improving code readability.