Jackson-jr 不支持 java.time.* 包，但我們可以使用自定義序列化器和反序列器添加它：

public class CustomDateSerializer implements ValueWriter {
    @Override
    public void writeValue (JSONWriter jsonWriter, JsonGenerator jsonGenerator, Object o) throws IOException {
        jsonGenerator.writeString(o.toString());
    }

    @Override
    public Class<?> valueType () {
        return LocalDate.class;
    }
}

public class CustomDateDeserializer extends ValueReader {
    private final static DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MMM-dd");

    public CustomDateDeserializer () {
        super(LocalDate.class);
    }

    @Override
    public Object read (JSONReader jsonReader, JsonParser jsonParser) throws IOException {
        return LocalDate.parse(jsonParser.getText(), dtf);
    }
}

在註冊它們之後，我們可以開始序列化和反序列化 LocalDate 對象：

public class MyHandlerProvider extends ReaderWriterProvider {

    @Override
    public ValueWriter findValueWriter (JSONWriter writeContext, Class<?> type) {
        if (type == LocalDate.class) {
            return new CustomDateSerializer();
        }
        return null;
    }

    @Override
    public ValueReader findValueReader (JSONReader readContext, Class<?> type) {
        if (type.equals(LocalDate.class)) {
            return new CustomDateDeserializer();
        }
        return null;
    }
}

Person person = new Person("John Doe", 30, LocalDate.now());

JSON jsonMapper = JSON.builder().register(new JacksonJrExtension() {
    @Override
    protected void register (ExtensionContext extensionContext) {
        extensionContext.insertProvider(new MyHandlerProvider());
    }   
}).build().with(JSON.Feature.PRETTY_PRINT_OUTPUT);

String json = jsonMapper.asString(person);
Person deserializedPerson = jsonMapper.beanFrom(Person.class, json);

5. Jackson-jr 與 Jackson