Jackson - accept empty string on Object property

user_6380991 0
Viewed 3887

I have POJO like this 

@Data
public class Tree {
   String id;
   Leaf leaf;
}

How to make, that my rest controller with RequestBody "Tree" will accept JSON request with empty String on property leaf, omitted it and treat as null. Example JSON Request

 {
      "id": "foo",
      "leaf": ""
 }
jackson spring json java
3 Answers

You have to set the ACCEPT_EMPTY_STRING_AS_NULL_OBJECT attribute of your ObjectMapper to true.

See the documentation :

Determines whether empty String value is accepted as null value for regular POJOs ("beans") with data-binding: this can be useful when dealing endpoints written in a language that has loose typing and may represent missing objects as Empty Strings.

If you're using Spring Boot, you can find details here on how to configure your ObjectMapper.

user_82327550

Configure the ObjectMapper as follows:

ObjectMapper om = new ObjectMapper();
om.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true);
user_6572240

You need to configure Jackson ObjectMapper to accept empty string as null. To do that simply add the following method in your configuration class.

@Bean
public ObjectMapper mapper() {
    ObjectMapper mapper = new ObjectMapper();
    mapper.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true);
    return mapper;
}
user_61712110
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