Deserialize JSON date format to ZonedDateTime using objectMapper

Question

Background

1. I have the following JSON (message from Kafka)

{
      "markdownPercentage": 20,
      "currency": "SEK",
      "startDate": "2019-07-25"
}

2. I have the following (JSON schema generated) POJO (I cannot change the POJO as it is shared resource in the company)

public class Markdown {
    @JsonProperty("markdownPercentage")
    @NotNull
    private Integer markdownPercentage = 0;
    @JsonProperty("currency")
    @NotNull
    private String currency = "";
    @JsonFormat(
        shape = Shape.STRING,
        pattern = "yyyy-MM-dd"
    )
    @JsonProperty("startDate")
    @NotNull
    private ZonedDateTime startDate;

    // Constructors, Getters, Setters etc.

}

3. Our application is a Spring Boot application which reads the JSON message (1) from Kafka using Spring Cloud Stream and uses the POJO (2) and then does stuff with it.

Problem

When the application tries to deserialize the message to the object it throws the following exception

com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.time.ZonedDateTime` from String "2019-07-25": Failed to deserialize java.time.ZonedDateTime: (java.time.DateTimeException) Unable to obtain ZonedDateTime from TemporalAccessor: {},ISO resolved to 2019-07-25 of type java.time.format.Parsed
 at [Source: (String)"{"styleOption":"so2_GreyMelange_1563966403695_1361997740","markdowns":[{"markdownPercentage":20,"currency":"SEK","startDate":"2019-07-25"},{"markdownPercentage":20,"currency":"NOK","startDate":"2019-07-25"},{"markdownPercentage":20,"currency":"CHF","startDate":"2019-07-25"}]}"; line: 1, column: 126] (through reference chain: com.bestseller.generated.interfacecontracts.kafkamessages.pojos.markdownScheduled.MarkdownScheduled["markdowns"]->java.util.ArrayList[0]->com.bestseller.generated.interfacecontracts.kafkamessages.pojos.markdownScheduled.Markdown["startDate"])

    at com.fasterxml.jackson.databind.exc.InvalidFormatException.from(InvalidFormatException.java:67)
    at com.fasterxml.jackson.databind.DeserializationContext.weirdStringException(DeserializationContext.java:1549)
    at com.fasterxml.jackson.databind.DeserializationContext.handleWeirdStringValue(DeserializationContext.java:911)
    at com.fasterxml.jackson.datatype.jsr310.deser.JSR310DeserializerBase._handleDateTimeException(JSR310DeserializerBase.java:80)
    at com.fasterxml.jackson.datatype.jsr310.deser.InstantDeserializer.deserialize(InstantDeserializer.java:212)
    at com.fasterxml.jackson.datatype.jsr310.deser.InstantDeserializer.deserialize(InstantDeserializer.java:50)
    at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:127)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:286)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:245)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:27)
    at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:127)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3004)
    at com.bestseller.mps.functional.TestingConfiguration.test(TestingConfiguration.java:42)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.time.DateTimeException: Unable to obtain ZonedDateTime from TemporalAccessor: {},ISO resolved to 2019-07-25 of type java.time.format.Parsed
    at java.base/java.time.ZonedDateTime.from(ZonedDateTime.java:566)
    at com.fasterxml.jackson.datatype.jsr310.deser.InstantDeserializer.deserialize(InstantDeserializer.java:207)
    ... 35 more
Caused by: java.time.DateTimeException: Unable to obtain ZoneId from TemporalAccessor: {},ISO resolved to 2019-07-25 of type java.time.format.Parsed
    at java.base/java.time.ZoneId.from(ZoneId.java:463)
    at java.base/java.time.ZonedDateTime.from(ZonedDateTime.java:554)
    ... 36 more

Current Code

I have the following objectMapper defined

/**
     * Date mapper.
     *
     * @return the {@link ObjectMapper}
     */
    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper mapper = new ObjectMapper();
        mapper.registerModule(new JavaTimeModule());
        mapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd"));
        return mapper;
    }

Question

I understand that the resulting ZonedDateTime in the POJO needs a 'time' element which is not present in the source message. I have control only over the objectMapper. Is there any possible configuration that can make this work ?

Note

I am fine if the time element in the deserialised POJO is "assumed" to be startOfDay i.e. "00.00.00.000Z"

Answer 1

I have control only over the ObjectMapper. Is there any possible configuration that can make this work?

As long as you are happy with default values for the time and for the timezone, you could work around it with a custom deserializer:

public class ZonedDateTimeDeserializer extends JsonDeserializer<ZonedDateTime> {

    @Override
    public ZonedDateTime deserialize(JsonParser jsonParser,
                                     DeserializationContext deserializationContext)
                                     throws IOException {

        LocalDate localDate = LocalDate.parse(
                jsonParser.getText(), 
                DateTimeFormatter.ISO_LOCAL_DATE);

        return localDate.atStartOfDay(ZoneOffset.UTC);
    }
}

Then add it to a module and register the module to your ObjectMapper instance:

SimpleModule module = new SimpleModule();
module.addDeserializer(ZonedDateTime.class, new ZonedDateTimeDeserializer());

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

---

If adding the deserializer to a module doesn't suit you (in the sense this configuration will be applied to other ZonedDateTime instances), then you could rely on mix-ins to define which fields the deserializer will be applied to. First define a mix-in interface, as shown below:

public interface MarkdownMixIn {

    @JsonDeserialize(using = ZonedDateTimeDeserializer.class)
    ZonedDateTime getDate();
}

And then bind the mix-in interface to the desired class:

ObjectMapper mapper = new ObjectMapper();
mapper.addMixIn(Markdown.class, MarkdownMixIn.class);

Answer 2

Problem: I would like to parse dates from json to java LocalDateTime/ZonedDateTime objects. ZonedDateTimeSerializer exists but the ZonedDateTimeDeserializer doesn't exist. Hence why I created a custom ZonedDateTimeDeserializer.

  public static final String ZONED_DATE_TIME_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSSz"; 

  @Getter
  @Setter
  @JsonSerialize(using = ZonedDateTimeSerializer.class)
  @JsonDeserialize(using = ZonedDateTimeDeserializer.class) // Doesn't exist, So I created a custom ZonedDateDeserializer utility class.
  @JsonFormat(pattern = ZONED_DATE_TIME_FORMAT)
  @JsonProperty("lastUpdated")
  private ZonedDateTime lastUpdated;

Solution: I ended up with simpler & fewer lines of code.

The Utility Class for deserialising the ZonedDateTime:

/**
 * Custom {@link ZonedDateTime} deserializer.
 *
 * @param jsonParser             for extracting the date in {@link String} format.
 * @param deserializationContext for the process of deserialization a single root-level value.
 * @return {@link ZonedDateTime} object of the date.
 * @throws IOException throws I/O exceptions.
 */
public class ZonedDateTimeDeserializer extends JsonDeserializer<ZonedDateTime> {

    @Override
    public ZonedDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext)
            throws IOException {

        return ZonedDateTime.parse(jsonParser.getText(), DateTimeFormatter.ofPattern(ZONED_DATE_TIME_FORMAT));
    }
}

What if you're using LocalDateTime instead. In that case it's even easier, both the deserializer & the serializer classes are already provided to us. No need for custom utility classes as defined above:

  @Getter
  @Setter
  @JsonSerialize(using = LocalDateSerializer.class)
  @JsonDeserialize(using = LocalDateTimeDeserializer.class)
  @JsonFormat(pattern = ZONED_DATE_TIME_FORMAT) //Specify the format you want: "yyyy-MM-dd'T'HH:mm:ss.SSS"
  @JsonProperty("created")
  private LocalDateTime created;

Other links that also helped with the research: ideas that led to this solution

Keywords: json format localDateTime zonedDateTime