How Can I Skip Null Values When Serializing Objects with Jackson?

Jackson: Skipping Null Values during Serialization

When serializing objects using Jackson, it can be desirable to exclude fields with null values to optimize data size and improve readability. To this end, Jackson offers two methods to achieve this behavior:

1. Global Configuration:

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

//...

ObjectMapper mapper = new ObjectMapper();
mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false); // disable serialization of null values

This setting applies globally to all serialization operations performed by the ObjectMapper instance.

2. @JsonInclude Annotation:

The @JsonInclude annotation can be applied to specific fields or classes to customize their serialization behavior. For example:

import com.fasterxml.jackson.annotation.JsonInclude;

//...

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

This annotation instructs Jackson to exclude the someValue field from serialization if its value is null.

Alternatively, the @JsonInclude annotation can be used on the getter method of the field:

import com.fasterxml.jackson.annotation.JsonInclude;

//...

public class SomeClass {
    private String someValue;

    @JsonInclude(JsonInclude.Include.NON_NULL)
    public String getSomeValue() {
        return someValue;
    }
}

This approach allows the field to be serialized only when its value is not null.

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