java - jackson 图书馆 : custom mapping of a Java object in a JSON element

Question

我有两个类(class)

public class Person {
    private long id;
    private String name;
    private Gender gender;

    // getter and setter omitted
}

和

public class Gender {
    private long id;
    private String value;

    // getter and setter omitted
}

默认情况下，Person 对象与 Jackson 库的 JSON 映射是:

{
   id: 11,
   name: "myname",
   gender: {
      id: 2,
      value: "F"
   }
}

我想知道如何配置 Jackson 以获得:

{
   id: 11,
   name: "myname",
   gender: "F"
}

我不想映射所有 Gender 对象，而只映射它的 value 属性。

Answer 1

您可以使用自定义序列化程序:

    public class GenderSerializer extends JsonSerializer<Gender> {

        public GenderSerializer() {
        }

        @Override
        public void serialize(Gender gender, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException {
               jgen.writeString(gender.getValue());        
        }
    }

在你的 Person 类中:

public class Person {
    private long id;
    private String name;
    @JsonSerialize(using = GenderSerializer.class)
    private Gender gender;

}