将带有嵌入对象的 Java 对象转换为带有属性列表和值列表的 JSON，反之亦然

Question

In my Spring project I have several objects that should be serialized to a specific JSON format.

public class Person {
   private Integer id;
   private String name;
   private String height;
   private Address address;
}

and

public class Address {
   private String street;
   private String city;
   private String phone;
}

Let assume that Person.height and Address.phone should not appear in the JSON. The resulting JSON should look like

{
  "attributes": ["id", "name", "street", "city"],
  "values": [12345, "Mr. Smith", "Main street", "Chicago"]
}

I can create create a standard JSON with an ObjectMapper and some annotations like @JsonProperty and @JsonUnwrapped where I disable some SerializationFeatures. But at the moment I'm not able to create such a JSON.

Is there an easy way to create this JSON? And how would the way back (deserialization) look like?

Answer 1

There are good reasons Jackson doesn't serializes maps in this format. It's less readable and also harder to deserialize properly.

But if you just create another POJO it's very easy to achieve what you want to do:

public class AttributeList {

    public static AttributeList from(Object o) {
        return from(new ObjectMapper().convertValue(o, new TypeReference<Map<String, Object>>() {}));
    }

    public static AttributeList from(Map<String, Object> attributes) {
        return new AttributeList(attributes);
    }

    private final List<String> attributes;
    private final List<Object> values;

    private AttributeList(Map<String, Object> o) {
        attributes = new ArrayList<>(o.keySet());
        values = new ArrayList<>(o.values());
    }

}