Jackson: how to serialize only annotated properties

Question

I would like to define my custom serialization strategy (which fields to include), while using Jackson. I know, that I can do it with views/filters, but it introduces very bad thing - using string-representation of field names, which automatically enables problems with auto-refactoring.

How do I force Jackson into serializing only annotated properties and nothing more?

Solution 1

If you disable all auto-detection it should only serialize the properties that you have annotated--whether it be the properties themselves or the getters. Here's a simple example:

private ObjectMapper om;

@Before
public void setUp() throws Exception {
    om = new ObjectMapper();
    // disable auto detection
    om.disable(MapperFeature.AUTO_DETECT_CREATORS,
            MapperFeature.AUTO_DETECT_FIELDS,
            MapperFeature.AUTO_DETECT_GETTERS,
            MapperFeature.AUTO_DETECT_IS_GETTERS);
    // if you want to prevent an exception when classes have no annotated properties
    om.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
}

@Test
public void test() throws Exception {
    BlahClass blahClass = new BlahClass(5, "email", true);
    String s = om.writeValueAsString(blahClass);
    System.out.println(s);
}

public static class BlahClass {
    @JsonProperty("id")
    public Integer id;
    @JsonProperty("email")
    public String email;
    public boolean isThing;

    public BlahClass(Integer id, String email, boolean thing) {
        this.id = id;
        this.email = email;
        isThing = thing;
    }
}

Solution 2

In case you want to do this without configuring the mapper just for a specific type:

@JsonAutoDetect(
    fieldVisibility = Visibility.NONE,
    setterVisibility = Visibility.NONE,
    getterVisibility = Visibility.NONE,
    isGetterVisibility = Visibility.NONE,
    creatorVisibility = Visibility.NONE
)
public class BlahClass {
    @JsonProperty("id")
    private Integer id;
    @JsonProperty("email")
    private String email;
}

Comments

[Denis Kulagin]

Works as a charm. You are thE bEst!

[Denis Kulagin]

Only to mention: it requires com.fasterxml.jackson.core.jackson-databind maven artifact-o.

[TemarV]

Thanks for providing this response. Jackson is serializing exactly how I want without having to go through a Mixin or CustomSerializer.

[MrAaronOlsen]

As of 2.13 ObjectMapper::disable has been deprecated. New approach is to use JsonMapper.Builder::.featuresToDisable. I used the provided Jackson2ObjectMapperBuilder as a convenience.