How to tell Jackson to ignore a field during serialization if its value is null?

Question

How can Jackson be configured to ignore a field value during serialization if that field\'s value is null.

For example:

public class SomeClass {
            


        

Answer 1

You can use the following mapper configuration:

mapper.getSerializationConfig().setSerializationInclusion(Inclusion.NON_NULL);

Since 2.5 you can user:

mapper.setSerializationInclusion(Include.NON_NULL);

Answer 2

Jackson 2.x+ use

mapper.getSerializationConfig().withSerializationInclusion(JsonInclude.Include.NON_NULL);

Answer 3

This Will work in Spring boot 2.0.3+ and Jackson 2.0+

import com.fasterxml.jackson.annotation.JsonInclude;

@JsonInclude(JsonInclude.Include.NON_NULL)
public class ApiDTO
{
    // your class variable and 
    // methods
}

Answer 4

Case one

@JsonInclude(JsonInclude.Include.NON_NULL)
private String someString;

Case two

@JsonInclude(JsonInclude.Include.NON_EMPTY)
private String someString;

If someString is null, it will be ignored on both of cases. If someString is "" it just only be ignored on case two.

The same for List = null or List.size() = 0

Answer 5

If you're trying to serialize a list of object and one of them is null you'll end up including the null item in the JSON even with

mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

will result in:

[{myObject},null]

to get this:

[{myObject}]

one can do something like:

mapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {
        @Override
        public void serialize(Object obj, JsonGenerator jsonGen, SerializerProvider unused)
                throws IOException
        {
            //IGNORES NULL VALUES!
        }
    });

TIP: If you're using DropWizard you can retrieve the ObjectMapper being used by Jersey using environment.getObjectMapper()

Answer 6

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonInclude(JsonInclude.Include.NON_EMPTY)

should work.

Include.NON_EMPTY indicates that property is serialized if its value is not null and not empty. Include.NON_NULL indicates that property is serialized if its value is not null.