Jackson 在 Spring Boot 中错误地序列化了 ZonedDateTime

Jackson serializes a ZonedDateTime wrongly in Spring Boot

我有一个带有 Spring Boot 和 Jetty 的简单应用程序。我有一个简单的控制器返回一个具有 Java 8 ZonedDateTime:

的对象
public class Device {
  // ...
  private ZonedDateTime lastUpdated;

  public Device(String id, ZonedDateTime lastUpdated, int course, double latitude, double longitude) {
    // ...
    this.lastUpdated = lastUpdated;
    // ...
  }

  public ZonedDateTime getLastUpdated() {
    return lastUpdated;
  }
}

在我的 RestController 中,我只有:

@RequestMapping("/devices/")
public @ResponseBody List<Device> index() {
  List<Device> devices = new ArrayList<>();
  devices.add(new Device("321421521", ZonedDateTime.now(), 0, 39.89011333, 24.438176666));

  return devices;
}

我原以为 ZonedDateTime 会根据 ISO 格式进行格式化,但我得到的是 class 的整个 JSON 转储,如下所示:

"lastUpdated":{"offset":{"totalSeconds":7200,"id":"+02:00","rules":{"fixedOffset":true,"transitionRules":[],"transitions":[]}},"zone":{"id":"Europe/Berlin","rules":{"fixedOffset":false,"transitionRules":[{"month":"MARCH","timeDefinition":"UTC","standardOffset":{"totalSeconds":3600,"id":"+01:00","rules":{"fixedOffset":true,"transitionRules":[],"transitions":[]}},"offsetBefore":{"totalSeconds":3600,"id":"+01:00","rules":{"fixedOffset":true,"transitionRules":[],"transitions":[]}},"offsetAfter":{"totalSeconds":7200,"id":"+02:00", ...

我只有一个 spring-boot-starter-web 应用程序,使用 spring-boot-starter-jetty 并排除 spring-boot-starter-tomcat

为什么 Jackson 在 Spring Boot 中表现如此?

** 更新**

对于那些正在寻找如何解决这个问题的完整分步指南的人,我在提出问题后发现了这个: http://lewandowski.io/2016/02/formatting-java-time-with-spring-boot-using-json/

有图书馆jackson-datatype-jsr310。试试吧。

此库涵盖了新的日期时间 API 并且还包括 ZonedDateTime 的序列化程序。

您只需添加 JavaTimeModule:

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JavaTimeModule());

更新

将日期时间转换为 ISO-8601 string you should disable WRITE_DATES_AS_TIMESTAMPS feature. You can easily do by either overriding ObjectMapper bean or by using application properties:

spring.jackson.serialization.WRITE_DATES_AS_TIMESTAMPS = false

如果您不依赖 SpringBoot 的自动配置功能 - 您没有在配置文件中提供 spring.jackson.serialization.WRITE_DATES_AS_TIMESTAMPS = false 属性 - 或者出于任何原因创建 ObjectMapper手动实例。您可以通过编程方式禁用此功能,如下所示:

ObjectMapper m = new ObjectMapper();
m.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

这是给杰克逊的 2.8.7

上面已经提到了答案,但我认为它缺少一些信息。对于那些希望以多种形式(不仅仅是 ZonedDateTime)解析 Java 8 个时间戳的人。您需要在 POM 中使用最新版本的 jackson-datatype-jsr310 并注册以下模块:

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.registerModule(new JavaTimeModule());
objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);

测试此代码

@Test
void testSeliarization() throws IOException {
    String expectedJson = "{\"parseDate\":\"2018-12-04T18:47:38.927Z\"}";
    MyPojo pojo = new MyPojo(ZonedDateTime.parse("2018-12-04T18:47:38.927Z"));

    // serialization
    assertThat(objectMapper.writeValueAsString(pojo)).isEqualTo(expectedJson);

    // deserialization
    assertThat(objectMapper.readValue(expectedJson, MyPojo.class)).isEqualTo(pojo);
}

请注意,您可以在 Spring 或 dropwizard 中全局配置对象映射器来实现此目的。我还没有找到一种干净的方法来在不注册自定义(反)序列化程序的情况下将其作为字段上的注释。

对于杰克逊 2.10 及以上,

parent pom.xml

<!-- https://github.com/FasterXML/jackson-bom -->
<dependencyManagement>
  <dependency>
    <groupId>com.fasterxml.jackson</groupId>
    <artifactId>jackson-bom</artifactId>
    <version>2.10.3</version>
    <type>pom</type>
    <scope>import</scope>
  </dependency>
</dependencyManagement>

模块pom.xml

<!-- https://github.com/FasterXML/jackson-modules-java8 -->
<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

JsonMapper 创建,可能在你的 @Configuration class

@Bean
public JsonMapper jsonMapper() {
    return JsonMapper.builder()
        .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
        .addModule(new JavaTimeModule())
        .build();
}

进一步阅读:

application.yml中的设置spring.jackson.serialization.write-dates-as-timestamps=false对我们的项目没有帮助。很可能是因为有其他库与 Jackson 一起工作:Swagger / OpenAPI / OpenAPI Generator。

有用的是将 RequestMappingHandlerAdapter@EventListener 添加到 @SpringBootApplication class。

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.context.event.EventListener;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;

@SpringBootApplication
public class SpringBootInitializer {

    @Autowired
    private RequestMappingHandlerAdapter handlerAdapter;

    public static void main(String[] args) {
        SpringApplication.run(SpringBootInitializer.class, args);
    }

    @EventListener
    public void handleContextRefresh(ContextRefreshedEvent event) {
        // see https://github.com/FasterXML/jackson-modules-java8/issues/11#issuecomment-913199874
        // spring.jackson.serialization.write-dates-as-timestamps=false setting does not work in our configuration (probably because of Swagger / OpenAPI / OpenAPI Generator libraries used)

        handlerAdapter
            .getMessageConverters()
            .forEach(c -> {
                if (c instanceof MappingJackson2HttpMessageConverter jsonMessageConverter) {
                    ObjectMapper objectMapper = jsonMessageConverter.getObjectMapper();
                    objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
                }
            });
    }
}

我在这里找到了这个解决方案 — https://github.com/FasterXML/jackson-modules-java8/issues/11#issuecomment-913199874