How Can I Prevent Jackson from Serializing Null Fields?

Skipping Null Field Serialization with Jackson

Jackson provides several ways to suppress the serialization of fields with null values. This can be useful for reducing the size of serialized data or for ensuring that certain fields are not exposed externally.

Configuring the ObjectMapper

To globally configure Jackson to ignore null values, you can set the SerializationInclusion property of the ObjectMapper:

mapper.setSerializationInclusion(Include.NON_NULL);

This will cause Jackson to skip any field with a null value during serialization.

Using the @JsonInclude Annotation

For individual fields, you can use the @JsonInclude annotation to control how null values are handled:

class SomeClass {
   @JsonInclude(Include.NON_NULL)
   private String someValue; 
}

With this annotation, the someValue field will only be serialized if it is not null.

Using @JsonInclude with Getters

Alternatively, you can use @JsonInclude in a getter method to selectively exclude fields based on the value:

class SomeClass {
   private String someValue; 

   @JsonInclude(value=Include.NON_NULL, content=Include.ALWAYS)
   public String getSomeValue() {
      return someValue;
   }
}

In this example, the someValue field will be excluded from serialization if it is null, but it will be included if it is not null, even if it is an empty string.

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