Right way to write JSON deserializer in Spring or extend it

Question

I am trying to write a custom JSON deserializer in Spring  I want to use default serializer for most part of fields and use a custom deserializer for few properties  Is it possible  I am trying this way because  most part of properties are values  so for these I can let Jackson use default deserializer  but few properties are references  so in the custom deserializer I have to query a database for reference name and get reference value from database   I ll show some code if needed

User · Accepted Answer

I ve searched a lot and the best way I ve found so far is on this article   Class to serialize  package net sghill example   import net sghill example UserDeserializer import net sghill example UserSerializer import org codehaus jackson map annotate JsonDeserialize  import org codehaus jackson map annotate JsonSerialize    JsonDeserialize using   UserDeserializer class  public class User       private ObjectId id      private String   username      private String   password       public User ObjectId id  String username  String password            this id   id          this username   username          this password   password             public ObjectId getId           return id        public String   getUsername     return username        public String   getPassword     return password        Deserializer class  package net sghill example   import net sghill example User  import org codehaus jackson JsonNode  import org codehaus jackson JsonParser  import org codehaus jackson ObjectCodec  import org codehaus jackson map DeserializationContext  import org codehaus jackson map JsonDeserializer   import java io IOException   public class UserDeserializer extends JsonDeserializer lt User gt          Override     public User deserialize JsonParser jsonParser  DeserializationContext deserializationContext  throws IOException           ObjectCodec oc   jsonParser getCodec            JsonNode node   oc readTree jsonParser           return new User null  node get  username   getTextValue    node get  password   getTextValue               Edit  Alternatively you can look at this article which uses new versions of com fasterxml jackson databind JsonDeserializer

User · Answer

I was trying to  Autowire a Spring-managed service into my Deserializer  Somebody tipped me off to Jackson using the new operator when invoking the serializers deserializers  This meant no auto-wiring of Jackson s instance of my Deserializer  Here s how I was able to  Autowire my service class into my Deserializer   context xml   lt mvc annotation-driven gt     lt mvc message-converters gt       lt bean class  org springframework http converter json MappingJackson2HttpMessageConverter  gt         lt property name  objectMapper  ref  objectMapper    gt       lt  bean gt     lt  mvc message-converters gt   lt  mvc gt   lt bean id  objectMapper  class  org springframework http converter json Jackson2ObjectMapperFactoryBean  gt       lt  -- Add deserializers that require autowiring -- gt       lt property name  deserializersByType  gt           lt map key-type  java lang Class  gt               lt entry key  com acme Anchor  gt                   lt bean class  com acme AnchorDeserializer    gt               lt  entry gt           lt  map gt       lt  property gt   lt  bean gt    Now that my Deserializer is a Spring-managed bean  auto-wiring works   AnchorDeserializer java  public class AnchorDeserializer extends JsonDeserializer lt Anchor gt         Autowired     private AnchorService anchorService      public Anchor deserialize JsonParser parser  DeserializationContext context               throws IOException  JsonProcessingException              Do stuff           AnchorService java   Service public class AnchorService        Update  While my original answer worked for me back when I wrote this   xi lin s response is exactly what is needed  Nice find

User · Answer

With Spring MVC 4 2 1 RELEASE  you need to use the new Jackson2 dependencies as below for the Deserializer to work   Dont use this   lt dependency gt                 lt groupId gt org codehaus jackson lt  groupId gt                 lt artifactId gt jackson-mapper-asl lt  artifactId gt                 lt version gt 1 9 12 lt  version gt             lt  dependency gt      Use this instead    lt dependency gt               lt groupId gt com fasterxml jackson core lt  groupId gt               lt artifactId gt jackson-annotations lt  artifactId gt               lt version gt 2 2 2 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 2 2 2 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 2 2 2 lt  version gt           lt  dependency gt      Also use com fasterxml jackson databind JsonDeserializer and  com fasterxml jackson databind annotation JsonDeserialize for the deserialization and not the classes from org codehaus jackson

[java] Right way to write JSON deserializer in Spring or extend it

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