使用 JacksonMapper 反序列化 Java 8 LocalDateTime [英] Deserialize Java 8 LocalDateTime with JacksonMapper

问题描述

我在 SO 中阅读了几个关于 java.time.LocalDateTime 和 JSON 属性之间的序列化和反序列化的问题和答案，但我似乎无法让它工作.

I have read several questions with answers here in SO concerning serialization and deserialization between java.time.LocalDateTime and JSON property but I can't seem to get it working.

我已设法将 Spring Boot 应用程序配置为以我想要的格式返回日期 (YYY-MM-dd HH:mm)，但我在接受 JSON 格式的值时遇到问题.

I have managed to configure my Spring Boot Application to return the dates in the format I desire (YYY-MM-dd HH:mm) but I have problems accepting values in this format in JSON.

这些是我迄今为止所做的所有事情:

These are all the things I have done so far:

为 jsr310 添加了 maven 依赖:

Added maven dependency for jsr310:

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

在我的主类中指定jsr310:

@EntityScan(basePackageClasses = { App.class, Jsr310JpaConverters.class })

禁用序列化作为 application.properties 中的时间戳:

Disabled serialization as timestamps in application.properties:

spring.jackson.serialization.write_dates_as_timestamps=false

这是我的日期时间实体映射:

And this is my entity mapping for datetime:

@Column(name = "start_date")
@DateTimeFormat(iso = DateTimeFormat.ISO.TIME)
@JsonFormat(pattern = "YYYY-MM-dd HH:mm")
private LocalDateTime startDate;

在我的数据库中，我以以下格式将此日期存储为 TIMESTAMP:2016-12-01T23:00:00+00:00.

In my database, I store this date as TIMESTAMP in the following format: 2016-12-01T23:00:00+00:00.

如果我通过我的控制器访问这个实体，它会以正确的 startDate 格式返回 JSON.当我尝试发布它并反序列化它时，使用 YYYY-MM-dd HH:mm 格式，我得到以下异常:

If I access this entity via my controller, it returns the JSON with correct startDate format. When I try to post it and deserialize it though, using YYYY-MM-dd HH:mm format, I get the following exception:

{
  "timestamp": "2016-10-30T14:22:25.285+0000",
  "status": 400,
  "error": "Bad Request",
  "exception": "org.springframework.http.converter.HttpMessageNotReadableException",
  "message": "Could not read document: Can not deserialize value of type java.time.LocalDateTime from String "2017-01-01 20:00": Text '2017-01-01 20:00' could not be parsed: Unable to obtain LocalDateTime from TemporalAccessor: {MonthOfYear=1, WeekBasedYear[WeekFields[SUNDAY,1]]=2017, DayOfMonth=1},ISO resolved to 20:00 of type java.time.format.Parsed
 at [Source: java.io.PushbackInputStream@679a734d; line: 6, column: 16] (through reference chain: com.gigsterous.api.model.Event["startDate"]); nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Can not deserialize value of type java.time.LocalDateTime from String "2017-01-01 20:00": Text '2017-01-01 20:00' could not be parsed: Unable to obtain LocalDateTime from TemporalAccessor: {MonthOfYear=1, WeekBasedYear[WeekFields[SUNDAY,1]]=2017, DayOfMonth=1},ISO resolved to 20:00 of type java.time.format.Parsed
 at [Source: java.io.PushbackInputStream@679a734d; line: 6, column: 16] (through reference chain: com.gigsterous.api.model.Event["startDate"])",
  "path": "/api/events"
}

我知道有很多关于这个话题的答案，但是关注他们并尝试了几个小时并没有帮助我弄清楚我做错了什么，所以如果有人能指出我遗漏了什么，我会很高兴.感谢您对此的任何意见！

I know that there are many answers concerning this topic but following them and trying for couple of hours did not help me to figure out what am I doing wrong so I would be glad if someone could point out to me what am I missing. Thanks for any input on this!

这些是过程中涉及的所有类:

These are all the classes involved in the process:

存储库:

@Repository
public interface EventRepository extends PagingAndSortingRepository<Event, Long> {
}

控制器:

@RequestMapping(method = RequestMethod.POST, consumes = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<Event> createEvent(@RequestBody Event event) {
        return new ResponseEntity<>(eventRepo.save(event), HttpStatus.CREATED);
}

我的JSON请求payalod:

My JSON request payalod:

{
  "name": "Test",
  "startDate": "2017-01-01 20:00"
}

事件:

@Entity
@Table(name = "events")
@Getter
@Setter
public class Event {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "event_id")
    private long id;

    @Column(name = "name")
    private String name;

    @Column(name = "start_date")
    @DateTimeFormat(iso = DateTimeFormat.ISO.TIME)
    @JsonFormat(pattern = "YYYY-MM-dd HH:mm")
    private LocalDateTime startDate;
}

推荐答案

您传递的日期时间不是 ISO 本地日期时间格式.

The date time you're passing is not an ISO local date time format.

改为

@Column(name = "start_date")
@DateTimeFormat(iso = DateTimeFormatter.ISO_LOCAL_DATE_TIME)
@JsonFormat(pattern = "YYYY-MM-dd HH:mm")
private LocalDateTime startDate;

并以2011-12-03T10:15:30"格式传递日期字符串.

and pass the date string in the format '2011-12-03T10:15:30'.

但如果您仍想传递自定义格式，则只需指定正确的格式化程序即可.

But if you still want to pass your custom format, you just have to specify the right formatter.

改为

@Column(name = "start_date")
@DateTimeFormat(iso = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"))
@JsonFormat(pattern = "YYYY-MM-dd HH:mm")
private LocalDateTime startDate;

我认为您的问题是 @DateTimeFormat 根本没有效果.由于 Jackson 正在执行反序列化，它对 Spring 注释一无所知，而且我没有看到 spring 在反序列化上下文中扫描此注释.

I think your problem is the @DateTimeFormat has no effect at all. As the Jackson is doing the deserialization and it doesn't know anything about spring annotation, and I don't see spring scanning this annotation in the deserialization context.

或者，您可以在注册 Java 时间模块时尝试设置格式化程序.

Alternatively, you can try setting the formatter while registering the Java time module.

LocalDateTimeDeserializer localDateTimeDeserializer = new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
module.addDeserializer(LocalDateTime.class, localDateTimeDeserializer);

这是带有去盐器的测试用例，它工作正常.也许尝试完全摆脱那个 DateTimeFormat 注释.

Here is the test case with the deseralizer which works fine. Maybe try to get rid of that DateTimeFormat annotation altogether.

@RunWith(JUnit4.class)
public class JacksonLocalDateTimeTest {

    private ObjectMapper objectMapper;

    @Before
    public void init() {
        JavaTimeModule module = new JavaTimeModule();
        LocalDateTimeDeserializer localDateTimeDeserializer =  new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
        module.addDeserializer(LocalDateTime.class, localDateTimeDeserializer);
        objectMapper = Jackson2ObjectMapperBuilder.json()
                .modules(module)
                .featuresToDisable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
                .build();
    }

    @Test
    public void test() throws IOException {
        final String json = "{ "date": "2016-11-08 12:00" }";
        final JsonType instance = objectMapper.readValue(json, JsonType.class);

        assertEquals(LocalDateTime.parse("2016-11-08 12:00",DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm") ), instance.getDate());
    }
}


class JsonType {
    private LocalDateTime date;

    public LocalDateTime getDate() {
        return date;
    }

    public void setDate(LocalDateTime date) {
        this.date = date;
    }
}

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