具有相同 JsonProperty 属性的不同字段

Question

Is it possible to have something like below while serializing a JSON in the same class

@JsonProperty("stats")
private StatsDetails statsDetails

@JsonProperty("stats")
private List<StatsDetails> statsDetailsList

so i can have either statsDetails or statsDetailsList only one of these being included while forming a json.

I also have a separate JsonMapper code that transforms this pojo data into a json which i haven't included here.

Answer 1

You cannot do that. It will throw JsonMappingException jackson cannot know which of the fields are you referring to. You can try it by yourself with the following code:

POJOClass:

import com.fasterxml.jackson.annotation.JsonGetter;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSetter;

import java.util.List;

public class POJOClass {

    public POJOClass(String object) {
        this.object = object;
    }

    public POJOClass(List<String> objectList) {
        this.objectList = objectList;
    }

    @JsonProperty("object")
    public String object;

    @JsonProperty("object")
    public List<String> objectList;
    @JsonGetter("object")
    public String getObject() {
        return object;
    }

    @JsonGetter("object")
    public List<String> getObjectList() {
        return objectList;
    }

    @JsonSetter("object")
    public void setObject(String object) {
        this.object = object;
    }

    @JsonSetter("object")
    public void setObjectList(List<String> objectList) {
        this.objectList = objectList;
    }
}

Main class:

import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;

public class MainClass {

    public static void main(String[] args) {
        String text = "f";
        List<String> list = Arrays.asList("a", "b", "c");
        ObjectMapper mapper = new ObjectMapper();
        try {
            String json = mapper.writeValueAsString(new POJOClass(text));
            String listJson = mapper.writeValueAsString(new POJOClass(list));
            System.out.println("json=" + json);
            System.out.println("listJson=" + listJson);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

The output:

com.fasterxml.jackson.databind.JsonMappingException: Multiple fields representing property "object": POJOClass#object vs POJOClass#objectList