Serializing enums with Jackson

Question

I have an Enum desrcibed below   public enum OrderType      UNKNOWN 0   Undefined      TYPEA 1   Type A      TYPEB 2   Type B      TYPEC 3   Type C       private Integer id    private String name     private WorkOrderType Integer id  String name        this id   id      this name   name           Setters  getters         I return enum array with my controller   new OrderType    UNKNOWN TYPEA TYPEB TYPEC     and Spring serializes it into the following json string     UNKNOWN    TYPEA    TYPEB    TYPEC      What is the best approach to force Jackson to serialize enums just like POJOs  E g          id   1   name    Undefined        id   2   name    Type A        id   3   name    Type B        id   4   name    Type C       I played with different annotations but couldn t manage to get such result

User · Answer

In Spring Boot 2  the easiest way is to declare in your application properties   spring jackson serialization WRITE ENUMS USING TO STRING true spring jackson deserialization READ ENUMS USING TO STRING true   and define the toString   method of your enums

User · Answer

Use  JsonCreator annotation  create method getType    is serialize with toString or object working     ATIVO     or    type    ATIVO    descricao    Ativo          import com fasterxml jackson annotation JsonCreator  import com fasterxml jackson annotation JsonFormat  import com fasterxml jackson databind JsonNode  import com fasterxml jackson databind node JsonNodeType    JsonFormat shape   JsonFormat Shape OBJECT  public enum SituacaoUsuario        ATIVO  Ativo        PENDENTE VALIDACAO  Pendente de Valida    o        INATIVO  Inativo        BLOQUEADO  Bloqueado                   Usuarios cadastrados pelos clientes que n  o possuem acesso a aplicacao         caso venham a se cadastrar este status deve ser alterado             NAO REGISTRADO  N  o Registrado         private SituacaoUsuario String descricao            this descricao   descricao             private String descricao       public String getDescricao             return descricao                TODO - Adicionar metodos dinamicamente     public String getType             return this toString               public String getPropertieKey             StringBuilder sb   new StringBuilder  enum             sb append this getClass   getName    append               sb append toString             return sb toString   toLowerCase                JsonCreator     public static SituacaoUsuario fromObject JsonNode node            String type   null          if  node getNodeType   equals JsonNodeType STRING                 type   node asText              else               if   node has  type                      throw new IllegalArgumentException                              type   node get  type   asText                      return valueOf type

User · Answer

An easy way to serialize Enum is using  JsonFormat annotation   JsonFormat can configure the serialization of a Enum in three ways    JsonFormat Shape STRING public Enum OrderType         uses OrderType  name as the serialization method  Serialization of OrderType TypeA is    TYPEA      JsonFormat Shape NUMBER Public Enum OrderTYpe        uses OrderType  ordinal as the serialization method  Serialization of OrderType TypeA is 1   JsonFormat Shape OBJECT Public Enum OrderType        treats OrderType as a POJO  Serialization of OrderType TypeA is   id  1  name   Type A    JsonFormat Shape OBJECT is what you need in your case   A little more complicated way is your solution  specifying a serializer for the Enum   Check out this reference  https   fasterxml github io jackson-annotations javadoc 2 2 0 com fasterxml jackson annotation JsonFormat html

User · Answer

JsonFormat shape  JsonFormat Shape OBJECT  public enum SomeEnum   available since https   github com FasterXML jackson-databind issues 24  just tested it works with version 2 1 2  answer to TheZuck   I tried your example  got Json      events     type   ADMIN       My code    RequestMapping value     getEvent    ResponseBody   public EventContainer getEvent         EventContainer cont   new EventContainer        cont setEvents Event values         return cont      class EventContainer implements Serializable      private Event   events     public Event   getEvents         return events       public void setEvents Event   events       this events   events         and dependencies are    lt dependency gt     lt groupId gt com fasterxml jackson core lt  groupId gt     lt artifactId gt jackson-annotations lt  artifactId gt     lt version gt   jackson version  lt  version gt   lt  dependency gt    lt dependency gt     lt groupId gt com fasterxml jackson core lt  groupId gt     lt artifactId gt jackson-core lt  artifactId gt     lt version gt   jackson version  lt  version gt   lt  dependency gt    lt dependency gt     lt groupId gt com fasterxml jackson core lt  groupId gt     lt artifactId gt jackson-databind lt  artifactId gt     lt version gt   jackson version  lt  version gt     lt exclusions gt       lt exclusion gt         lt artifactId gt jackson-annotations lt  artifactId gt         lt groupId gt com fasterxml jackson core lt  groupId gt       lt  exclusion gt       lt exclusion gt         lt artifactId gt jackson-core lt  artifactId gt         lt groupId gt com fasterxml jackson core lt  groupId gt       lt  exclusion gt     lt  exclusions gt   lt  dependency gt    lt jackson version gt 2 1 2 lt  jackson version gt

User · Answer

Here is my solution  I want transform enum to  id       name       form   With Jackson 1 x   pom xml    lt properties gt       lt jackson version gt 1 9 13 lt  jackson version gt   lt  properties gt    lt dependencies gt       lt dependency gt           lt groupId gt org codehaus jackson lt  groupId gt           lt artifactId gt jackson-core-asl lt  artifactId gt           lt version gt   jackson version  lt  version gt       lt  dependency gt       lt dependency gt           lt groupId gt org codehaus jackson lt  groupId gt           lt artifactId gt jackson-mapper-asl lt  artifactId gt           lt version gt   jackson version  lt  version gt       lt  dependency gt   lt  dependencies gt    Rule java   import org codehaus jackson map annotate JsonSerialize  import my NamedEnumJsonSerializer  import my NamedEnum    Entity  Table name    RULE   public class Rule        Column name    STATUS   nullable   false  updatable   true       Enumerated EnumType STRING       JsonSerialize using   NamedEnumJsonSerializer class      private Status status      public Status getStatus     return status        public void setStatus Status status    this status   status         public static enum Status implements NamedEnum           OPEN  open rule            CLOSED  closed rule            WORKING  rule in work             private String name          Status String name    this name   name            public String getName     return this name               NamedEnum java   package my   public interface NamedEnum       String name        String getName        NamedEnumJsonSerializer java   package my   import my NamedEnum  import java io IOException  import java util    import org codehaus jackson JsonGenerator  import org codehaus jackson JsonProcessingException  import org codehaus jackson map JsonSerializer  import org codehaus jackson map SerializerProvider   public class NamedEnumJsonSerializer extends JsonSerializer lt NamedEnum gt         Override     public void serialize NamedEnum value  JsonGenerator jgen  SerializerProvider provider  throws IOException  JsonProcessingException           Map lt String  String gt  map   new HashMap lt  gt             map put  id   value name             map put  name   value getName             jgen writeObject map             With Jackson 2 x   pom xml    lt properties gt       lt jackson version gt 2 3 3 lt  jackson version gt   lt  properties gt    lt dependencies gt       lt dependency gt           lt groupId gt com fasterxml jackson core lt  groupId gt           lt artifactId gt jackson-core lt  artifactId gt           lt version gt   jackson version  lt  version gt       lt  dependency gt       lt dependency gt           lt groupId gt com fasterxml jackson core lt  groupId gt           lt artifactId gt jackson-databind lt  artifactId gt           lt version gt   jackson version  lt  version gt       lt  dependency gt   lt  dependencies gt    Rule java   import com fasterxml jackson annotation JsonFormat    Entity  Table name    RULE   public class Rule        Column name    STATUS   nullable   false  updatable   true       Enumerated EnumType STRING      private Status status      public Status getStatus     return status        public void setStatus Status status    this status   status          JsonFormat shape   JsonFormat Shape OBJECT      public static enum Status           OPEN  open rule            CLOSED  closed rule            WORKING  rule in work             private String name          Status String name    this name   name            public String getName     return this name            public String getId     return this name                 Rule Status CLOSED translated to  id   CLOSED   name   closed rule

User · Answer

Finally I found solution myself   I had to annotate enum with  JsonSerialize using   OrderTypeSerializer class  and implement  custom serializer   public class OrderTypeSerializer extends JsonSerializer lt OrderType gt        Override   public void serialize OrderType value  JsonGenerator generator              SerializerProvider provider  throws IOException              JsonProcessingException        generator writeStartObject        generator writeFieldName  id        generator writeNumber value getId         generator writeFieldName  name        generator writeString value getName         generator writeEndObject

User · Answer

I ve found a very nice and concise solution  especially useful when you cannot modify enum classes as it was in my case  Then you should provide a custom ObjectMapper with a certain feature enabled  Those features are available since Jackson 1 6   public class CustomObjectMapper extends ObjectMapper        PostConstruct     public void customConfiguration                Uses Enum toString   for serialization of an Enum         this enable WRITE ENUMS USING TO STRING              Uses Enum toString   for deserialization of an Enum         this enable READ ENUMS USING TO STRING             There are more enum-related features available  see here   https   github com FasterXML jackson-databind wiki Serialization-features https   github com FasterXML jackson-databind wiki Deserialization-Features

[java] Serializing enums with Jackson

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