Deserialize Java 8 LocalDateTime with JacksonMapper

Question

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.

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.

These are all the things I have done so far:

Added maven dependency for jsr310:

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

Specified jsr310 in my main class:

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

Disabled serialization as timestamps in application.properties:

spring.jackson.serialization.write_dates_as_timestamps=false 

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; 

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

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\n 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\n at [Source: java.io.PushbackInputStream@679a734d; line: 6, column: 16] (through reference chain: com.gigsterous.api.model.Event[\"startDate\"])",   "path": "/api/events" } 

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!

EDIT: These are all the classes involved in the process:

Repository:

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

Controller:

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

My JSON request payalod:

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

Event:

@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; } 

Answer 1

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

Change to

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

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

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

Change to

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

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.

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); 

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;     } } 

Answer 2

You used wrong letter case for year in line:

@JsonFormat(pattern = "YYYY-MM-dd HH:mm") 

Should be:

@JsonFormat(pattern = "yyyy-MM-dd HH:mm") 

With this change everything is working as expected.