Spring REST Service how to configure to remove null objects in json response

Question

I have a spring webservice that returns a json response  I m using the example given here to create the service  http   www mkyong com spring-mvc spring-3-mvc-and-json-example   The format the json is returned in is    name  null  staffName    kfc-kampar   smith     I want to remove any null objects from the returned response so it looks like this    staffName    kfc-kampar   smith     I ve found similar questions asked here but I ve been able to get a solution working e g   Configuring ObjectMapper in Spring  How to configure MappingJacksonHttpMessageConverter while using spring annotation-based configuration   configuring the jacksonObjectMapper not working in spring mvc 3  how to configure spring mvc 3 to not return  quot null quot  object in json response   Spring configure  ResponseBody JSON format  Jackson Spring3 0 5 custom object mapper  From reading through these and other sources  I figured the cleanest way to achieve what I wanted was to use Spring 3 1 and the message-converters that can be configured within the mvc-annotation   My updated spring config file is    lt beans xmlns  http   www springframework org schema beans  xmlns context  http   www springframework org schema context  xmlns mvc  http   www springframework org schema mvc   xmlns xsi  http   www w3 org 2001 XMLSchema-instance  xsi schemaLocation       http   www springframework org schema beans          http   www springframework org schema beans spring-beans-3 1 xsd     http   www springframework org schema context      http   www springframework org schema context spring-context-3 1 xsd     http   www springframework org schema mvc     http   www springframework org schema mvc spring-mvc-3 1 xsd  gt    lt context component-scan base-package  com mkyong common controller    gt    lt mvc annotation-driven gt       lt mvc message-converters gt           lt bean class  org springframework http converter json MappingJacksonHttpMessageConverter  gt               lt property name  prefixJson  value  true    gt               lt property name  supportedMediaTypes  value  application json    gt               lt property name  objectMapper  gt                   lt bean class  org codehaus jackson map ObjectMapper  gt                       lt property name  serializationInclusion  value  NON NULL   gt                   lt  bean gt               lt  property gt           lt  bean gt       lt  mvc message-converters gt   lt  mvc annotation-driven gt      The service class is the same as given on the mkyong com site  except I commented out the setting of the Shop name variable so it s null i e    Controller  RequestMapping   kfc brands   public class JSONController        RequestMapping value   name    method   RequestMethod GET       ResponseStatus HttpStatus OK       public  ResponseBody Shop getShopInJSON  PathVariable String name            Shop shop   new Shop              shop setName name           shop setStaffName new String   name   cronin             return shop            The Jackson jars I m using are jackson-mapper-asl 1 9 0 and jackson-core-asl 1 9 0  These are the only new jars I ve added to the pom as provided as part of the spring-json project I downloaded from mkyong com   The project builds successfully  but when I invoke the service through the browser I still get the same thing i e    name  null  staffName    kfc-kampar   smith     Can anyone tell me where I m going wrong with my configuration    I ve tried several other options  but the only way I ve been able to return the json in the correct format is to add the Object mapper to the JSONController and have the  getShopInJSON  method return a string i e   public  ResponseBody String getShopInJSON  PathVariable String name  throws JsonGenerationException  JsonMappingException  IOException       ObjectMapper mapper   new ObjectMapper        mapper setSerializationInclusion JsonSerialize Inclusion NON NULL        Shop shop   new Shop          shop setName name       shop setStaffName new String   name   cronin         String test   mapper writeValueAsString shop       return test      Now if I invoke the service I get the expected i e    staffName    kfc-kampar   cronin     I ve also been able to get it to work using the  JsonIgnore annotation  but this solution isn t suitable for me   I don t understand why it s working in code but not in the configuration  so any help would be fantastic

User · Answer

I ve found a solution through configuring the Spring container  but it s still not exactly what I wanted   I rolled back to Spring 3 0 5  removed  and in it s place I changed my config file to        lt bean     class  org springframework web servlet mvc annotation AnnotationMethodHandlerAdapter  gt       lt property name  messageConverters  gt           lt list gt               lt bean                 class  org springframework http converter json MappingJacksonHttpMessageConverter  gt                   lt property name  objectMapper  ref  jacksonObjectMapper    gt               lt  bean gt           lt  list gt       lt  property gt   lt  bean gt     lt bean id  jacksonObjectMapper  class  org codehaus jackson map ObjectMapper    gt   lt bean id  jacksonSerializationConfig  class  org codehaus jackson map SerializationConfig      factory-bean  jacksonObjectMapper  factory-method  getSerializationConfig    gt   lt bean     class  org springframework beans factory config MethodInvokingFactoryBean  gt       lt property name  targetObject  ref  jacksonSerializationConfig    gt       lt property name  targetMethod  value  setSerializationInclusion    gt       lt property name  arguments  gt           lt list gt               lt value type  org codehaus jackson map annotate JsonSerialize Inclusion  gt NON NULL lt  value gt           lt  list gt       lt  property gt   lt  bean gt    This is of course similar to responses given in other questions e g    configuring the jacksonObjectMapper not working in spring mvc 3  The important thing to note is that mvc annotation-driven and AnnotationMethodHandlerAdapter cannot be used in the same context    I m still unable to get it working with Spring 3 1 and mvc annotation-driven though  A solution that uses mvc annotation-driven and all the benefits that accompany it would be far better I think  If anyone could show me how to do this  that would be great

User · Answer

You can use JsonWriteNullProperties for older versions of Jackson   For Jackson 1 9   use JsonSerialize include

User · Answer

JsonSerialize include JsonSerialize Inclusion NON EMPTY  public class Shop                 for jackson 2 0 or later use  JsonInclude Include NON NULL   This will remove both empty and null Objects

User · Answer

As of Jackson 2 0   JsonSerialize include   xxx  has been deprecated in favour of  JsonInclude

User · Answer

Since Jackson 2 0 you can use JsonInclude   JsonInclude Include NON NULL  public class Shop

User · Answer

For all you non-xml config folks      ObjectMapper objMapper   new ObjectMapper   setSerializationInclusion JsonInclude Include NON NULL   HttpMessageConverter msgConverter   new MappingJackson2HttpMessageConverter objMapper   restTemplate setMessageConverters Collections singletonList msgConverter

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If you are using Jackson 2  the message-converters tag is    lt mvc annotation-driven gt       lt mvc message-converters gt           lt bean class  org springframework http converter json MappingJackson2HttpMessageConverter  gt               lt property name  prefixJson  value  true   gt               lt property name  supportedMediaTypes  value  application json   gt               lt property name  objectMapper  gt                   lt bean class  com fasterxml jackson databind ObjectMapper  gt                       lt property name  serializationInclusion  value  NON NULL   gt                   lt  bean gt               lt  property gt           lt  bean gt       lt  mvc message-converters gt   lt  mvc annotation-driven gt

User · Answer

Since version 1 6 we have new annotation JsonSerialize  in version 1 9 9 for example    Example    JsonSerialize include Inclusion NON NULL  public class Test          Default value is ALWAYS   In old versions you can use  JsonWriteNullProperties  which is deprecated in new versions   Example    JsonWriteNullProperties false  public class Test

User · Answer

Setting the spring jackson default-property-inclusion non null option is the simplest solution and it works well   However  be careful if you implement WebMvcConfigurer somewhere in your code  then the property solution will not work and you will have to setup NON NULL serialization in the code as the following    Configuration  EnableWebMvc public class WebConfig implements WebMvcConfigurer          some of your config here          Override     public void configureMessageConverters List lt HttpMessageConverter lt   gt  gt  converters            ObjectMapper objectMapper   new ObjectMapper            objectMapper setSerializationInclusion JsonInclude Include NON NULL           MappingJackson2HttpMessageConverter jsonConverter   new MappingJackson2HttpMessageConverter objectMapper           converters add jsonConverter

User · Answer

Since Jackson is being used  you have to configure that as a Jackson property  In the case of Spring Boot REST services  you have to configure it in application properties or application yml   spring jackson default-property-inclusion   NON NULL   source

[java] Spring REST Service: how to configure to remove null objects in json response

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