Force Milliseconds When Serializing Instant to ISO8601 using Jackson

Question

I have some questions related to JSON serialization using Jackson in a project where I use Spring Boot 2.0.0.M6, Spring Framework 5.0.1.R

Answer 1

There appears to be a Jackson issue open for this here*. That link contains two workarounds

Workaround 1

 ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.registerModule(new JavaTimeModule());
    SimpleModule module = new SimpleModule();
    module.addSerializer(ZonedDateTime.class, new JsonSerializer() {
        @Override
        public void serialize(ZonedDateTime zonedDateTime, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException, JsonProcessingException {
            jsonGenerator.writeString(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSZZZ").format(zonedDateTime));
        }
    });
    objectMapper.registerModule(module);
    objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
    objectMapper.enable(SerializationFeature.INDENT_OUTPUT);

Workaround 2

JavaTimeModule javaTimeModule = new JavaTimeModule();
javaTimeModule.addSerializer(ZonedDateTime.class,
  new ZonedDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSX")));
ObjectMapper mapper = new ObjectMapper().registerModule(javaTimeModule);

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^{*Link is dead because they deprecated FasterXML/jackson-datatype-jsr310 and moved it to jackson-modules-java8. See https://github.com/FasterXML/jackson-modules-java8/issues/76}