How to skip wrapper object in jackson json deserialization

You can create a custom annotation with @JsonDeserialize inside and create a custom JsonDeserializer that implements ContextualDeserializer. The idea is inspired from the solution you mentioned but it is more general to unwrap any one property in a json object.

Following is the custom annotation using @JacksonAnnotationsInside as annotation container contains @JsonDeserialize:

@Retention(RetentionPolicy.RUNTIME)@JacksonAnnotationsInside@JsonDeserialize(using = JsonUnwrapPropertyDeserializer.class)public @interface JsonUnwrapProperty {}

and the custom JsonDeserializer that implements ContextualDeserializer:

public class JsonUnwrapPropertyDeserializer extends JsonDeserializer<Object> implements ContextualDeserializer {    private JavaType unwrappedJavaType;    private String unwrappedProperty;    @Override    public JsonDeserializer<?> createContextual(final DeserializationContext deserializationContext, final BeanProperty beanProperty) throws JsonMappingException {        unwrappedProperty = beanProperty.getMember().getName();        unwrappedJavaType = beanProperty.getType();        return this;    }    @Override    public Object deserialize(final JsonParser jsonParser, final DeserializationContext deserializationContext) throws IOException {        final TreeNode targetObjectNode = jsonParser.readValueAsTree().get(unwrappedProperty);        return jsonParser.getCodec().readValue(targetObjectNode.traverse(), unwrappedJavaType);    }}

and the usage example:

public class MyBean {    @JsonProperty("broadcastPresenceRoles")    @JsonUnwrapProperty    private List<String> broadcastPresenceRole;    @JsonProperty("admins")    @JsonUnwrapProperty    private String admin;    // constructor, getter and setter}

@JsonProperty is to locate the wrapper object and @JsonUnwrappProperty is to deserialize the json object and extract a property into the annotated field.

Edited:

Following is an example with ObjectMapper:

String json = "{\n" +        "  \"broadcastPresenceRoles\": {\n" +        "    \"broadcastPresenceRole\": [\n" +        "      \"moderator\",\n" +        "      \"participant\",\n" +        "      \"visitor\"\n" +        "    ]\n" +        "  },\n" +        "  \"admins\": {\n" +        "    \"admin\": \"sanjeet@shahanshah\"\n" +        "  }\n" +        "}";final ObjectMapper mapper = new ObjectMapper();final MyBean myBean = mapper.readValue(json, MyBean.class);System.out.println(myBean.getBroadcastPresenceRole());System.out.println(myBean.getAdmin());

Output:

[moderator, participant, visitor]

sanjeet@shahanshah

I created a variation that solved the NPE based on @wilson response

import java.io.IOException;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import com.fasterxml.jackson.annotation.JacksonAnnotationsInside;import com.fasterxml.jackson.core.JsonParser;import com.fasterxml.jackson.core.JsonToken;import com.fasterxml.jackson.databind.BeanProperty;import com.fasterxml.jackson.databind.DeserializationContext;import com.fasterxml.jackson.databind.JavaType;import com.fasterxml.jackson.databind.JsonDeserializer;import com.fasterxml.jackson.databind.JsonMappingException;import com.fasterxml.jackson.databind.annotation.JsonDeserialize;import com.fasterxml.jackson.databind.deser.ContextualDeserializer;@Retention(RetentionPolicy.RUNTIME)@JacksonAnnotationsInside@JsonDeserialize(using = JsonUnwrapProperty.JsonUnwrapPropertyDeserializer.class)public @interface JsonUnwrapProperty {  public static class JsonUnwrapPropertyDeserializer extends JsonDeserializer<Object>      implements ContextualDeserializer {    private JavaType unwrappedJavaType;    private String unwrappedProperty;    @Override    public JsonDeserializer<?> createContextual(final DeserializationContext deserializationContext,        final BeanProperty beanProperty) throws JsonMappingException {      unwrappedProperty = beanProperty.getMember().getName();      unwrappedJavaType = beanProperty.getType();      return this;    }    @Override    public Object deserialize(final JsonParser jsonParser, final DeserializationContext deserializationContext)        throws IOException {      System.out.println(String.format("Ignoring %s in %s/%s", unwrappedProperty,        jsonParser.currentName(), jsonParser.nextFieldName()));      JsonToken token = jsonParser.nextValue();      return jsonParser.getCodec().readValue(jsonParser, unwrappedJavaType);    }  }}