json如何为java定制全局jackson反序列化器。时间LocalDateTime

Question

Jackson的JavaTimeModule在全局范围内很好地序列化/反序列化java.time，但是它的默认日期时间格式是ISO标准的，比如2018-01-10T10:20:30表示LocalDateTime，而2018-01-10T10:20:30+08:00表示OffsetDateTime。但是我需要为LocalDateTime和OffsetDateTime设置一个全局本地格式，比如2018-01-10 10:20:30，而不使用T和OffsetTime（使用本地默认OffsetTime）。我该怎么做

Notes: I know about @JsonFormat, @JsonSerialize and @JsonDeserialize. That is not global setting.

Answer 1

如果您在全局范围内使用ObjectMapper的单个实例（并且想要一个独立于Spring/Java 8 jackson模块的解决方案），您可以执行以下操作：

public ObjectMapper getCustomConfigMapper() {
    final ObjectMapper mapper = new ObjectMapper();
    final SimpleModule module = new SimpleModule();
    module.addDeserializer(LocalDateTime.class, new CustomLocaDateTimeDeserializer());
    mapper.registerModule(module);
    return mapper;
}

public static class CustomLocaDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {

    public static final DateTimeFormatter CUSTOM_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

    @Override
    public LocalDateTime deserialize(JsonParser jsonParser, DeserializationContext __) throws IOException {
        final String value = jsonParser.getText().strip();
        return LocalDateTime.parse(value, CUSTOM_FORMATTER);
    }
}

Answer 2

弹簧靴

    @SpringBootApplication
    public class Application implements Jackson2ObjectMapperBuilderCustomizer {
        public static void main(String[] args) {
            SpringApplication.run(Application.class, args);
        }

        @Override
        public void customize(Jackson2ObjectMapperBuilder builder) {
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
            LocalDateTimeSerializer localDateTimeSerializer = new LocalDateTimeSerializer(formatter);

            builder.failOnEmptyBeans(false) // prevent InvalidDefinitionException Error
                    .serializerByType(LocalDateTime.class, localDateTimeSerializer);
        }
    }

Springboot&；Spring框架

    @Configuration
    public class WebMvcConfig implements WebMvcConfigurer {
        @Override
        public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
            LocalDateTimeSerializer localDateTimeSerializer = new LocalDateTimeSerializer(formatter);
            LocalDateTimeDeserializer localDateTimeDeserializer = new LocalDateTimeDeserializer(formatter);

            JavaTimeModule module = new JavaTimeModule();
            module.addSerializer(LocalDateTime.class, localDateTimeSerializer);
            module.addDeserializer(LocalDateTime.class, localDateTimeDeserializer);

            ObjectMapper mapper = new ObjectMapper();
            mapper.registerModule(module);
            // add converter at the very front
            // if there are same type mappers in converters, setting in first mapper is used.
            converters.add(0, new MappingJackson2HttpMessageConverter(mapper));
        }
    }

希望这能对你有所帮助

Answer 3

可以配置ObjectMapper。本页解释如何https://www.baeldung.com/jackson-serialize-dates。我想你想在这一页上找到与例4相近的内容

然后，您需要将其设置为全局对象映射器。不同的框架使用不同的方法。本页介绍如何在Spring和Spring boot Configuring ObjectMapper in Spring中实现这一点。对于其他人，只需谷歌搜索即可