serialize deserialize java 8 java time with Jackson JSON mapper

Question

How do I use Jackson JSON mapper with Java 8 LocalDateTime      org codehaus jackson map JsonMappingException  Can not instantiate value of type  simple type  class java time LocalDateTime  from JSON String  no single-String constructor factory method  through reference chain  MyDTO  field1  - SubDTO  date

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lt dependency gt               lt groupId gt com fasterxml jackson module lt  groupId gt               lt artifactId gt jackson-module-parameter-names lt  artifactId gt           lt  dependency gt           lt dependency gt               lt groupId gt com fasterxml jackson datatype lt  groupId gt               lt artifactId gt jackson-datatype-jdk8 lt  artifactId gt           lt  dependency gt           lt dependency gt               lt groupId gt com fasterxml jackson datatype lt  groupId gt               lt artifactId gt jackson-datatype-jsr310 lt  artifactId gt           lt  dependency gt   add these dependencies and enable these modules  that should help     private static final ObjectMapper mapper   new ObjectMapper   findAndRegisterModules

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This is just an example how to use it in a unit test that I hacked to debug this issue  The key ingredients are   mapper registerModule new JavaTimeModule     maven dependency of  lt artifactId gt jackson-datatype-jsr310 lt  artifactId gt    Code   import com fasterxml jackson databind ObjectMapper  import com fasterxml jackson datatype jsr310 JavaTimeModule  import org testng Assert  import org testng annotations Test   import java io IOException  import java io Serializable  import java time Instant   class Mumu implements Serializable       private Instant from      private String text       Mumu Instant from  String text            this from   from          this text   text             public Mumu                public Instant getFrom             return from             public String getText             return text              Override     public String toString             return  Mumu                      from     from                      text      text                                       public class Scratch          Test     public void JacksonInstant   throws IOException           ObjectMapper mapper   new ObjectMapper            mapper registerModule new JavaTimeModule              Mumu before   new Mumu Instant now     before            String jsonInString   mapper writeValueAsString before             System out println  -- BEFORE --            System out println before           System out println jsonInString            Mumu after   mapper readValue jsonInString  Mumu class           System out println  -- AFTER --            System out println after            Assert assertEquals after toString    before toString

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This maven dependency will solve your problem    lt dependency gt       lt groupId gt com fasterxml jackson datatype lt  groupId gt       lt artifactId gt jackson-datatype-jsr310 lt  artifactId gt       lt version gt 2 6 5 lt  version gt   lt  dependency gt    One thing I ve struggled is that for ZonedDateTime timezone being changed to GMT during deserialization  Turned out  that by default jackson replaces it with one from context    To keep zone one must disable this  feature   Jackson2ObjectMapperBuilder json        featuresToDisable DeserializationFeature ADJUST DATES TO CONTEXT TIME ZONE

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If you are using Jackson Serializer  here is a way to use the date modules   import com fasterxml jackson core JsonProcessingException  import com fasterxml jackson databind ObjectMapper  import com fasterxml jackson datatype jdk8 Jdk8Module  import com fasterxml jackson datatype jsr310 JavaTimeModule  import com fasterxml jackson module paramnames ParameterNamesModule  import org apache kafka common serialization Serializer   public class JacksonSerializer lt T gt  implements Serializer lt T gt         private final ObjectMapper mapper   new ObjectMapper                registerModule new ParameterNamesModule                 registerModule new Jdk8Module                 registerModule new JavaTimeModule           Override     public byte   serialize String s  T object            try               return mapper writeValueAsBytes object             catch  JsonProcessingException e                e printStackTrace                      return null

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You may set this in your application yml file to resolve Instant time  which is Date API in java8   spring jackson serialization write-dates-as-timestamps false

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If you consider using fastjson  you can solve your problem  note the version    lt dependency gt           lt groupId gt com alibaba lt  groupId gt           lt artifactId gt fastjson lt  artifactId gt           lt version gt 1 2 56 lt  version gt    lt  dependency gt

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If you are using ObjectMapper class of fasterxml   by default ObjectMapper do not understand the LocalDateTime class  so  you need to add another dependency in your gradle maven     compile  com fasterxml jackson datatype jackson-datatype-jsr310 2 7 3    Now you need to register the datatype support offered by this library into you objectmapper object  this can be done by following     ObjectMapper objectMapper   new ObjectMapper    objectMapper findAndRegisterModules      Now  in your jsonString  you can easily put your java LocalDateTime field as follows           user id   1       score   9       date time    2016-05-28T17 39 44 937      By doing all this  your Json file to Java object conversion will work fine  you can read the file by following     objectMapper readValue jsonString  new TypeReference lt List lt User gt  gt

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all you need to know is in Jackson Documentation https   www baeldung com jackson-serialize-dates Ad 9 quick solved the problem for me  ObjectMapper mapper   new ObjectMapper    mapper registerModule new JavaTimeModule     mapper disable SerializationFeature WRITE DATES AS TIMESTAMPS

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I had a similar problem while using Spring boot  With Spring boot 1 5 1 RELEASE all I had to do is to add dependency    lt dependency gt       lt groupId gt com fasterxml jackson datatype lt  groupId gt       lt artifactId gt jackson-datatype-jsr310 lt  artifactId gt   lt  dependency gt

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There s no need to use custom serializers deserializers here  Use jackson-modules-java8 s datetime module      Datatype module to make Jackson recognize Java 8 Date  amp  Time API data types  JSR-310     This module adds support for quite a few classes    Duration Instant LocalDateTime LocalDate LocalTime MonthDay OffsetDateTime OffsetTime Period Year YearMonth ZonedDateTime ZoneId ZoneOffset

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If you are using Spring boot and have this issue with the OffsetDateTime then need to use the registerModules as answered above by  greperror answered May 28  16 at 13 04  but note that there is one difference  The dependency mentioned doesn t need to be added as I am guessing that spring boot has it already  I was having this issue with Spring boot and it worked for me without adding this dependency

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Update  Leaving this answer for historical reasons  but I don t recommend it  Please see the accepted answer above   Tell Jackson to map using your custom  de serialization classes    JsonSerialize using   LocalDateTimeSerializer class   JsonDeserialize using   LocalDateTimeDeserializer class  private LocalDateTime ignoreUntil    provide custom classes   public class LocalDateTimeSerializer extends JsonSerializer lt LocalDateTime gt         Override     public void serialize LocalDateTime arg0  JsonGenerator arg1  SerializerProvider arg2  throws IOException           arg1 writeString arg0 toString              public class LocalDateTimeDeserializer extends JsonDeserializer lt LocalDateTime gt         Override     public LocalDateTime deserialize JsonParser arg0  DeserializationContext arg1  throws IOException           return LocalDateTime parse arg0 getText               random fact   if i nest above classes and don t make them static  the error message is weird  org springframework web HttpMediaTypeNotSupportedException  Content type  application json charset UTF-8  not supported

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If you can t use jackson-modules-java8 for whatever reasons you can  de- serialize the instant field as long using  JsonIgnore and  JsonGetter  amp   JsonSetter   public class MyBean        private Instant time   Instant now          JsonIgnore     public Instant getTime             return this time             public void setTime Instant time            this time   time              JsonGetter     private long getEpochTime             return this time toEpochMilli                JsonSetter     private void setEpochTime long time            this time   Instant ofEpochMilli time             Example    Test public void testJsonTime   throws Exception       String json   new ObjectMapper   writeValueAsString new MyBean         System out println json       MyBean myBean   new ObjectMapper   readValue json  MyBean class       System out println myBean getTime         yields    epochTime  1506432517242  2017-09-26T13 28 37 242Z

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If you re having this issue because of GraphQL Java Tools and trying to marshal an Java Instant from a date string  you need to setup your SchemaParser to use an ObjectMapper with certain configurations   In your GraphQLSchemaBuilder class  inject ObjectMapper and add this modules           ObjectMapper objectMapper        new ObjectMapper   registerModule new JavaTimeModule                 configure SerializationFeature WRITE DATES AS TIMESTAMPS  false     and add it to the options   final SchemaParserOptions options   SchemaParserOptions newOptions                objectMapperProvider fieldDefinition - gt  objectMapper               typeDefinitionFactory new YourTypeDefinitionFactory                 build      See https   github com graphql-java-kickstart graphql-spring-boot issues 32

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For those who use Spring Boot 2 x   There is no need to do any of the above - Java 8 LocalDateTime is serialised de-serialised out of the box  I had to do all of the above in 1 x  but with Boot 2 x  it works seamlessly    See this reference too JSON Java 8 LocalDateTime format in Spring Boot

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I use this time format    birthDate    2018-05-24T13 56 13Z   to deserialize from json into java time Instant  see screenshot

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If you are using Jersey then you need to add the Maven dependency  jackson-datatype-jsr310  as the others suggested and register your object mapper instance like so    Provider public class JacksonObjectMapper implements ContextResolver lt ObjectMapper gt       final ObjectMapper defaultObjectMapper     public JacksonObjectMapper         defaultObjectMapper   createDefaultMapper            Override   public ObjectMapper getContext Class lt   gt  type        return defaultObjectMapper         private static ObjectMapper createDefaultMapper         final ObjectMapper mapper   new ObjectMapper            mapper registerModule new JavaTimeModule         return mapper          When registering Jackson in your resources  you need to add this mapper like so   final ResourceConfig rc   new ResourceConfig   packages   lt your package gt     rc    register JacksonObjectMapper class     register JacksonJaxbJsonProvider class

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If any one having problem while using SpringBoot here is how I fixed the issue without adding new dependency   In Spring 2 1 3 Jackson expects date string 2019-05-21T07 37 11 000 in this yyyy-MM-dd HH mm ss SSS format to de-serialize in LocalDateTime  Make sure date string separates the date and time with T not with space  seconds  ss  and milliseconds SSS  could be ommitted     JsonProperty  last charge date   public LocalDateTime lastChargeDate

[jackson] serialize/deserialize java 8 java.time with Jackson JSON mapper

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